Document zbM0GxDG5oxkv5ajGp9xKaqVm

t+r, W.M ' Journal of Economic Entomology ENTOMOLOGICAL SOCIETY OF AMERICA August 15,1969 No. 4 Biological Interaction Between Plasticizers and Insecticides1 l.ianrNm:iN, K. R. Sciiui.x, T. W. Fuhrkmann, and T. T, Lianc. ' Department of Entomology, University of Wisconsin, Madison 53500 fhtAiiM' nf the Kinirtnrnl similarity to DDT-rclaled II plasticizers were tested for their loxlcolog- 0| iHtirKlIon wltlt cllrlclrjn aipl Dl>% Matty of these ,,4nhlmlii#lrd hiphenyl coinpounds wort toxic to Dro*oUifs mrl*mrinitrr Mt-lgcn and hottsc Dies, Mitsrn domes* W I.* Imt lo a lesser extent than dlcldrin or DDT. Tlieir toxicity Increased with a decrease in their chlorine content. Moreover, sitblcthal dosages of several of (he plasticisers Increased live toxicity of dlcldrin and DDT. Since plasticizers arc In live environment, their potential effects on biological systems, especially in combination with other synthetic chemicals, should not be disregarded. rUuirl/m melt as polychlorinated biphenyls arc aaltly (IfelritMilcd In the environment (Risebrough rt jI. IWM). Whlmark (I9fi7) rc|>or(cd mat extracts nf srs cxcKi, pike, and salmon contained polyrhlori* atirti blpncnyl plnstlcir.crs (PCB). Holmes cl al. (I9f>7). trhntird that jtolychlorinatcd biphenyl compounds hr.1 tics'll detected in British wildlife. T hey also stated dut "in birds' liver* ami eggs they arc often in greater Miuiiliilf* than organochlorinc itestkide residues." Airman ct Hi. (1969) found chlorinated biphenyls in Mt. hiium Is, and birds from the River Rhine anti the N'rthrrlamls coastal areas aiu| staled that the PCill impmiii<ii, "besides being a hazard in their own "(In" nloo ''interfere.with the detection of orgnno- dihahic inserticIdes snth as DDT." J'ldnldoHtinitd biphenyls arc produced by various nMnularturcrs in different countries. Some of them nt marketed utider the name of Aroclor* by the MuhmiMo Chemical Co., St. Louis. They represent . *s writ'* of inert, chcmicnMy-rcsistant,. fire-retarding hUliti/rti compatible witli a wide variety of resins. Ihrt vary from mobile! oily Moulds to while crystals ml Wtl transparent resins'* (Monsanto 1908). They ne used in- synthetic resins, synthetic and natural tHMiers. rt'llhhsse resins, paint, varnish, wax, asphalt, iml Ih allyl. starch, They also find Applications for 4mm pmrution. moisture proofing, sealing, imnreg- fidun; jind vn|Mir stippremion to' prolong the residual hit nf liisect hides. "Chlorinated polyphcnyls" were mnmiiM'ndctl In I0BH for "Improving lindane real*, ibn" (llumstein and Sullivan 1953). The authors tMirtl that "lindane residues cati be made to last kmgiT ami look better" if applied with chlorinated Hypfanyls,. ' t IrwhvH tor fwbtkstlob hf the' Dtrcftnr. of the WUcnmtn wSMturst Estr'immi Station.- This MiHty wat Mippmied In Nit h> hmNir llrsMti Snvke Arwsrth CrSnt CC-M2A7 from the NMMM .CammwMteahle' IMseaie Center, Atlanta, Gs. Contribution n itrWIiiMMis Asrinihiwa) Cfenerimrnl Station n a roftabo- *#4 MMtv North CrMtil Kemnal Cooperative Itnnnli Meet n, mtllM, ReiliMilon of llamriW AiaectatM with the Presence of imthttt M iMRiMrist Chtmtrals t * " ?x!a7n.Kii3.w"*?s5 The toxicity of polychlorinated biphenyl com pounds was briefly reviewed by Von Oettingen (1955) who reported that "feeding rats about 0.S gm daily was highly toxic when given over a period of six days and that even 0.05 am per rat was deftnltcly toxic, causing Injury to the liver." According to the same source, the toxicity to rats of chlorodiphenyl by inhalation was already studied in 1997 and some Itcpatoxic action was found. The threshold limits (maximum allowable concentration for an S-hr working day) was set by the American Conference of Government Hygienists (1953) as 1.0 to 0.5 mg of polychlorinated biphenyl comisoomls/m* or air. The present study was conducted to investigate the effects of some plasticizers on insects, both singly and In combination with dlcldrin or DDT. Materials and Methods.--The insecticides and in* scctfcklc metabolites used in this study were analytical grade lindane, hcptachlor, Itcptachlor epoxide, atdrin, dicldrin, o,p'*DDT, P,p' l)l)T, p,/>'-DDE, and p,p'TDK. Klcvcti polychlorinated bi* or tripbcnyl stand ards were obtained through the courtesy of Dr. R. F. Thomas, USDA, Hcltsvillc, Md. They arc referred to In this study, as plasticizers A through K and are iden tified in Table 9 with various Aroclors according to their Monsanto identification number. The plasticizers A through H contain 2 phenyl rings, anti their chlorinc content increases from A to H. Plasticizer I is a mixture of chlorinated biphenyls and chlorinated tri phenyls (60:40), and J and k are chlorinated tri phenyls. liiontxny Procedures.--The effects of the II plasti cizers, dicldrin, and DDT on Insects were tester! with Drosophiin melonogaster Mclgcn and with house flies, Musca domestic* L,, DDT-susccptible, CSMA-lfMS strain. (a) In 1 series of experiments, the effects of each chemical on ituicct mortalities were investigated. When D. metonoMifer were used, 8 ml of hexane containing either 0.1 me of dicldrin, 9.0 Mg of DDT, 200 or 800 Mg of plasticizers A, B, C, and D, and 2000 Mg of plasticizers through K were pipetted into 4-ot HONS 086953 *yin V',: ; "i 'y I .' .J 6. > <; i : . ' I :.* *; r . r 762 Journal op Economic Entomology Vol. 42, no. 4' btoassay jars (Edwards et at. 1957). Solvent! were . then evaporated end fifty 8-day-old /), mdanogastcr were Introduced Into cadi of duplicated test jin that . now contained the dry residue of the various chemi- cali: Mortality counu were performed after tf and 49- hr exposure times. ' In addition to these tests, Miyold adult female house files were treated topically on the ventral por- lion of the abdomen with 2 filter of acetone contain ing either 0.02 ps of dieldrin, 0.5 pg of DDT, or 10 and 20 uff of each of the plasticizers. Controls were treated with 2 filter of acetone only. After 90 house flick had been treated with each of the chemicals as described, they were held in 2 groups of 19 within 2 bioassay jars for 24 hr, then mortality counts were , made. (b) The 2nd scries of bioaisays was designed to . test the combined, and possibly synergistic, effects of the plasticizers with either dicldrin or DDT. For thU purpose, 0. melattogastcr flies were exposed to either 200 pg each of Use plasticizers, 0.1 Mg of dicldrin, or 8.0 Mg of DDT. when insecticides only were used (controls), 0.1 ml of hexane containing 280 Mg of corn oil was added to the insecticide solution in the . bioassay jars to eliminate lost of dieldrin or DDT , from the glass surfaces. In addition, flies were exposed to the combined dry residue of 0.1 Mg of dicldrin and 200 Mg of either 1 of the plasticizers, or to the combined residue of 9.0 Mg of DDT and 200 Mg of 1 of the II plasticizers. These experiments were replicated 4 times, each replicate consisting of 50 V. melanogaster files. . With house Hies, 2 aliter of acetone containing either 0.015 Mg of dicldrin, 0.9 Mg of PUT or 10 Mg of Uic plasticizers A, B, C, D, and E were applied topi* tally to tire ventral portion of 45 insects which were |tcpt in grou|M of 15 within 8 bioassay jars. In addi tion, 2 filter of acetone containing both dieldrin (0.015 Mg) and ! of the plasticizers (M Mg), or DDT ' (0.8 Mg) >nd I of the plasticizers (10 Mg) were ap plied as described. The treated house flies were then held for 24 hr when mortality counts were made. Statistical analyses of die data were performed with . the t-test. Chromniogmphic Ituhawor of Pliu/icizrrs.--To ob . tain some knowledge about the chromatographic be havior of the 11 pUstlcizen, they were dissolved in redistilled hexane anti analyzed by gas-liquid chro* maioeraphy (GLC) and thin layer chromatography ri LC).' lor comparison purposes the above-men tioned insecticides and metabolites were handled the ' same way For tests by GLC. 2 instruments with 2 different columns were employed in these investigations. One instrument was a Packard gat chromatograph, Model 7894. equipped with a 150-mCi tritium electron affin ity ionization detector operated at 50 v. A 1.89-m glass column (410 mm id) containing 5% SE 90 on 60(80 Chromosorb W AW-DMCS was conditioned for 7 days at 250*C before use. A column pressure of 25 psi of nitrogen resulted' in a flow rate of 125 mi/ min. Thie injector temperature was maintained at 240*C, the detector cell at 215*C, and die oven tem perature at I90*C. The 2nd instrument was a Tarrcll-Ash gas chromato? graph, Model 28-700 equipped with a 100-mCI tritium electron affinity ionization detector and operated at 20 v.; A 1,22-m glass column (4.0 mm id) containing a 1:1 mixture of5% QF 1 ana 5ft DC 200 coated on Anakrom A8, #0- to 00-mcsli, wm conditioned for 7 days at 250*C before use. A column pressure of 16 fsi of nitrogen gave a flow rate of 100 ml/min. The njcctor temperature was maintained at 250*C, the detector cell at 2I0*C, and die oven tcmticralurc at I90*C. One Mhtcr of hexane containing a mixture of insec ticides (9x 10~* Mg of lindane, 5x 10* Mg of hf|Ma<hlor and uldrin, IxlO*4 Mg of heptachlor cjmxide, DDE, and dicldrin, 2x10 * Mg of DDT and TDE) was In jected onto the column in each of the 2 gas chroma tographs. After all of the insecticide peaks had been recorded, 2 Milter of hexane containing 1 of the II plasticizers (2x10 * ag of A, B, C, D, E, or F, 5x10* Mg of G or H, 8x 10 * Mg of I, f, or K) were injected and tested in the same way. To compare the result ing chromatograms, retention times of the various peaks were calculated in reference to the retention time observed with aldrin. For tests by TI.C, 10 pg of each of the II plasti cizers were spotted on aluminum oxide G-coatetl glass plates (20x20 cm), 2.5 cm above the lower edge. In addition, 10 fig of each of the insecticides anti some of their metabolites were also spotted for reference. The chromatograms were then developed with 1% acetone in n-heptane, sprayed with reagent as de scribed by Mitchell (1957) and exposed to UV light for 50 min. Results and Discussion.--7Vie Effect of Phulicitert on Insects.'-Since the polychlorinated biphenyls are of toxicological interest, both their toxicity to insects and their interaction with insecticides were studied in 2 series of experiments, as previously described. (a) Dicldrin, DDT, or any one of the leas chlori nated and more volatile plasticisers (A, B, C, D, E) were toxic to both test insects (Table I). White these polychlorinated biphenyls contain increasing amounts of chlorine, their toxicity towards the insects decreased (A>B>C>D>E). Dieldrin was the most toxic of Tabic I.--Effect of plasticisers or InscctkMct on Insect mortalities. Material D. m< lsno|sjiler Applied* % mortality (*s) 24 hr 48 hr House flies Applied* (,/ r> % mor tality ~ttht None* Dieldrin :p,p'-DDT Plasticizers* A B C D K r-k 0.1 9.0 800 800 200 800 200 800 200 800 2000 2000 0 91 24 0 57 0 35 0 40 0 15 0 0 0 84 58 0 92 0 64 4 75 0 45 0 0 1.0 25.0 500 1000 500 1000 500 1000 500 1000 1000 1000 0 79 57 17 . 43 10 90 17 to 15 13 10 0 Applied In I ml hexane to 4 m glam Jars. D. metosogwle, posed id dry residue. ^Applied topically ( house dies la I alder a( acetone. Wright <4 1 draw mg. , * Controls were (rested with solvents only. > d Letters A to a refer to Aroekrs Htted to Table S. 51 f; lb I In th df wi be I wt 0i is s a g* i she plo IMS (H , et i C obi bee chi* I Float Aroci HSL 129F1242 1248 1254tm 128Itr 3 Tb*. MGNS 086954 ml -5i t mu- I t s sa*7 * 3 3- f ? * ? .1 Si r ts=s 1969 LrcHTt^rm: al.: PutsnciutR-lNSEcnctDE Interaction 769 the compounds, measured by the percent mortality ' Table 2.--Combined effects of plaetidten and insecti I the Imtoi within a 24- Or 48-hr exposure period. cide* on huecl*. Approximately 25 and SO times more DDT than diet- drill, and 6000 and 1000 times more plasticizers than dleldrin nad to be used to obtain similar mortalities ( !). sf/mog(r or of house flies, respectively, % mortalities of insects after exposure to within a given time of exposure to 'these chemicals, Maid- ' No insec- llie more highly chlorinated and less volatile plasti diets* ticlde Dicldrin p.p'-DDT cizers were nontoxic even when used at dosages of fflOO *g with D, melanogaster and 20 pg/fty (1000 lf/g fly) with lipusc flics. (0) Tabic 2 summarises .^ the results obtained after None' A the insects' had been ex|osc<l. to sublcthal dosages D . . tWO pg for D, melono^axter, 10 pg/house fly) of either C 11 of die plasticizers A, It, C, 1), or E and in combina D tion with dleldrin or DDT. Though no appreciable E D. melanogastcr e/fer 49 Ar* 0 60* 6 0 87* 4* 0 SI* 9* 9*2 77* 9 0 72* 4 0 JO* 94 59*0 99*9* 84*0* 89*6* 77*1* 47*9* insect mortalities were observed with plasticisers alone, iltcV significantly increased the toxic effects of both dleldrin and: DDT, This effect was most noticeable with J)I>T on 'house flics and differences observed were highly significant. After a 24*hr exposure period, of die house flies'had died after only DDT had been applied.' However, all the Insects were killed None A B C D E . House flies* after 24 hr . 0 27* 5 4 49* 9* 4 27* 5 0 47* 5' 98*11* 0 24* 0 98*9 100* 100* 98*9* 100* 100* when liDT was applied in combination with any one . of these plasticisers., The polychlorinated bipiienyls oho increased the toxic effect of DDT with D. melon* igoifer,-but to a ipssef extent./the most striking ef* feet' was observed with compound A. Plasticiser* F, J_..Mvr..fRD.i.fe,.t.f.e.m.dr...s.e.r..p.fM.M_.o._a.s.Al.cl,,.r.a_ee..U_e.t._l.rot.rh_.r.et_.w.._(.ecA_.rh*ec_lea_ekxE_pa)o_ks_a:e*_dpl.iU.n.IenNd.ld4_la-iier.snTe-,-iaag---a-bSla-aOl-se-Ss--I---w.Ja<- r*,,dlkeM...tr.h.lae, . sd.rly -- DDT, I S mm. ikoHay Jars withoal plMtkJsrn containetf ISO m et cent ell 0, H, I, J, and K applied with dleldrin or DDT to glass surfaces to which D. tnefanogtuler were exposed reduced the toxldty Of the Insecticide, resulting In *S'*>*lNllcrcncea obaemd between treatBnHi with ihe leaectkl enlr and ibese with Hwrctklde phn plaatkiaer are sifnllcnt at t d b 1%, as 1.1%, or (w 9% levef , . . Cbrmkah were applied topkallr In I piker el acetone le beox mortalities of 90% to none whhli)48 hr. In die absence of^additional data, no conclusions Rf. Comroll onir acetone was appaeo. weigm a 1 it should be drawn concerning the Combined effects of plMli$i*m, and insecticides in tissues of higher ani mals. 'However, plasticisers are in the environment. (Holmes et at 1M7, Rlsebrough ct al. 1968, Kocman ct ai. i960) and their potential hazards, cspcdatly In heptachlor, hcptachlor epoxide, aldrin, dicldrin, DDT, DuE, and TDK. The injection of nearly all of else plasticizers resulted in chromatograms with a multi combinatioii With other synthetic chemicals, should tude of peaks, sometimes as many as 15. Photographs not be disregarded.' . ,. of thin layer plates, prepared as previously described, CiraMifopsp/itV .Behatnor of /'/fufieixer*.--Results are presented in Fig. 1 and 2. Since analyses of most obtained after solutions of the 11 plasticisers had plasticizers by CLC resulted in chromatograms with beds analysed with 2 different columns In separate gas many peaks, it is conceivable that each of these plasti Chromatographs are fummarltcd in Table 9. The ob cisers represents a multitude of compounds that were served retention times were compared as described not separated by TLC as described, thus resulting in with those obtained after the injection of lindane, 1 or 2 spots only. Table Comparison of plnrttdsero end insecticides by CLC. Plasticiser Aroclor 1211-2* .1192-2 1242-1 IMM 1254-2 1200-2 1KI-2 1108-2 4465-2,9 . M42-9 9460*9 % weight No. ol chlorine peaks OLCI* Identical with* No. of peaks CLC IP Identical with* A .'21 I..1' None 9 LI B 'J 1 tt ' 15 LI. HE. AL. DE. DI.TD, DT 19 LI, HE.HO.DE C 42 14 LI. HE. AL, DE. Dl. TD. 14 LI. HE, HO, DF. D 41 \ 15 U, HE, AL, DE, DI, TD, DT 15 LI, HE, HO, DE. DT E 94 NI1 AL, Dg, DI, TD, DT 10 HO. DE, TD, DT F . 00 15 TD.DT 19 DI, TD, DT .0; 62 12 ' TD 19 DI.TD, DT a 68 1 \ None >.. 8 None 1 . 65 11 \ TD 11 DI J X 42 ' 9 60 9 None ' None .` . . 7 LI, HE, HO 0 None ' Si!1%% SfIlM on mm Cbreaneerb W. Oven snap IS*S&`0,.&;. w: i, | WcMoriasted tripbeayls. . . ' .. iee*c, - fcP'-DDT, DB DDE, MONS 086955 r 764 Journal or Economic Entomology VoL 62, no. f AufmtK FRONT ALORiN 4% p p'> o d c vw '-00T o PP'-ODT f, OOO^tTOC) , LINOANC " A0L .$* **v:1 fov'A HEPTACMLON I R|. M. EPOXIDE M DICLDRiS' I. (TO. * PRR.OI M I1 Amrr. O Anh. Habwi) I (Mm IMk l * Vo E I lie tr ItchinM | brunt tm a atNgfr Ii Ikm rmgr reprmlmcti i'. ALONIN 'I. ` pp'-DDE > 1 , PP-ODT 4V * Ft <> ' ^ ' o HtPTACHLOR | pp'-DDT ,jDDD ITDE) +. LINDANE * w . fn*t H. EFOXIOC OIELDRIN ' .Q , *TB- f O H I J K TO. '. , ' .. RC> pr POT _ Fm. I (above)Thlnlayof chromalopam ol plMllciteri A, . C, D, and E on aluminum oxide C. Solvenli 1% acclonc In nhepianc. STD m lnrrclklde atandardi (or comparlaon. H?. t (below) --Thin layer chromatogram of plaukiaen F. G, 11,1, 1, and K on aluminum oxide G. Solvent: I * acetone In Tt'hrpt.nr, STD m InaectlcliK atandarda (or comparlaon. HONS 066956 4fM> IM l.tCMTKNITKIN KT PLASTICIKR-INSECTICIT>F. INTERACTION 705 REFERENCE* CITED Aincr. Cmf. Gov. Ind. HnblNi, Lot Angela. 1959, . Arh. Imt. Hyg. Occnp. Mai. B: 290. firfwM*, C A., 8. D. Beck, and E. P. UdMrmlWn. 1957, , ftln*May oi alililn ami llmltnc in soil. J. Eton. En* lomol. 50: $f(-6. fc ^ J> H. Ilmmorn, am) |. O. G. Tation. IM7. Chlorlnilca hydrocarbons in British wlldlirc. Nature |l$t (27. Hormfctn, I* and W. N. Sullivan. 1959. The role of chlorinated polyphcnyls In Improving lindane resi dues, J. Econ. Emmol. 4$: 997-40. . Mann, J. II. M. C Ten Noevrr de Branw, and Jl. H. . df Vaa. 1981. Chlorinated btplienyli In flili. mumcis and bird* from the river Rhine and the Netherlands coastal area. Nature 221:' 1120. Mitchell, L. C. 1957. Ascending paper chromatography: A way to do It. J. Am. Agr. Chcm. 40: 999. Monsanto. 1961. Aroclor# plaslicirm. Tech. Dull.. 0/ PI.-S06. Monsanto Organic Chemicals Division. Jt lAMlit. Rlsebrough, R. W., P. Rlrthr, D. P. rrakatl. S. G. Her* man, and M. N. Kirvcn. 1968. Polychlorinated bl* . phenyls in tire global ecosystem. Nature (20: 1098. Von Oettingcn. W. P. 1965. Tlie halogcnatcd hydrocar- o Irons--toxicity and potential dangers. U. $. Public ' Health Serv. Publ. no. 414. p. Mo. Wldmark, G. 1967. Residue anatysis of pcstkklcs with lire aid ol gas chromatography. Sixth Int. Congr. Plant Protect. (Abstr.) Effect of Temperature on the Progeny Production and Longevity of Ltspesia archipptvora' in the Laboratory' ' . J>. E, JiavAN. C. G. Jackson, and Ravmono Patana ' Entomology Research Division. Agr. Rea. Sent., USDA, Tucson, Arliona 86719 ABSTRACT The reproduction and the' lifespan of die female lachlnld parasite IsipetUt irehippivor* (Riley) in the MmratOty were directly related to temperature. *llc urgnl number .of off spring (425) was obtained from a uncle female held at ICC; the means of total produc tion ragged from IS to 15*C to 225 at 25aC. Wlien reproductive activity was-measured St the mean number of puparia ptoduccd per ovlpositlon day. activity appeared to peak (15.9) at 30*C. Mean female longevity ranged from 40 to 59 days at )5*C to 12 to 16 days at S*C depemling on the length of the daily ovtpositlon period J4 or 6.5 hr).' Most oviposltion occurred before the 15th ay after eciotion. Istbftin nrchipphmm (Riley) is a widely distrib uted Indigenous parasite of many common lepidopterows pests of cro|N in North America, among which the bollworm, Hrliothu are (Doddle), and the to bacco btidwonn. H. virescem (F.). arc clearly (lie. most Important. The prevalence and apparent cli matic adaptability of`inis tadiinid seem to give it treat potential as a biological control agent if enough lieu can be made available at a given time. In our previous work with otchippivom (Bryan et a). 19GB) we described a rearing technique, re ported tlie tithes required for development at several temperatures, and discussed the possibility of produc ing the parasite in the laboratory. T'he present paper describes research on larval production and length of female fly life, 2 factors which arc'of obvious impor tance In a tftasM-cming program that would he neces sary If immdativc rrlcnaci are undertaken. Mtritons anr Materiam.--Adult archipphrora were obtained by the rearing technique described by Bryan ft al. (1968) with beet ahnyworms,' Spodoptcra nigua (HObncr), as the laboratory host. Pairs of Bin were removed from the rearing cages the day of edosion and as they were mating. To facilitate detertnination of female longevity, the males were marked with a fluorescent pigment dissolved in. alcohol, and each pair was placed jn a sepuatratie cage. These cages were the lower halves of S.B-litcr cardboard food con* ialners that had both ends screened with nylon (17x 17 irtcsh/234 cm*). A piece of sponge (ipohtened dally to provide water) and u sugar cube were placed In each cage and fastened to the bottom. ft \ , . V, - In the 1st teat (1967). the pairs were placed in constant-temperature cabinets maintained at 15, 20, 25, 80, or 95 I *C immediately after they were caged. In the 2nd test (1968), each pair was caged, ana all ftairt were held at room tcm/wraiurc S25.6~27.B*C) or 2 days to permit oftgenesis to proceed at the same pace. Then the pairs were placed in constant-temperaturc cabinets as before. In both tests, 4 replicates were tested simultaneously at each temperature. The 4th day after the flics became adults and daily throughout the lifespan of the female, 20 4th* and/or 5th-instnr beet armynvorm larvae were placed on die upfscr (screened) surface of each cage and confined there for 6.5 hr (1st test) or 4 hr (2nd test) by placing the lid of a 150-mm-diam glass petri dish over them. T he female flics oviposited through the nylon screen. After each daily exposure the beet armyworm lar vae were removed and placed in individual 9i*-oa clear plastic creamers partly filled with lima beanagar diet (Sborey 1965, Botigcr and J'atann 1966) that were then covered with paper lids. Records were made daily of the life of tlie flics, the number of host larvae offered for oviposltion, and the number of host larvae recovered. (Occasionally some were lost because of cannibalism or because they escaped.) The creamers containing the host larvae were held at room temperature for 14 days. Then the degree of parasitisation was determined by the pres ence or absence of fly puparia. T'he number of pupai ia produced was used as tnc measure of fecundity, be cause counting the eggs as they were laid was impos sible, and dissecting each host larva to determine the number of maggots It contained was impractical. This .method of assessment probably underestimates the MONS 086957