BIOLOGY OF THE LOTUS BOEEE. H 



aquatic environment, is well taken, for manj^ leaf and tree-feeding 

 caterpillars, exposed to the same or to greater risks, do not construct 

 protective webs and. on the other hand, many larvae living in 



sheltered and well-protected situations do build burrows or webs 



Avithin which to work. Be that as it. may, there is probably little 

 danger of wind or waves washing these caterpillars off the leaves. 



DIPTEROUS PARASITES. 



From living enemies, however, they do not escape so easily. Ac- 

 cording to the literature four species of tachinid flies have been 

 reared from the larvee. Townsend (6) lists Exoris'ta hirsuta. O. S. 

 (now" E. vulgaris Fall.) and Phorocera comstockii Will, as having 

 been reared by Forbes in Illinois. Coquillett (7, p. 17, 19) adds 

 Hypostena variahilis Coq. and Panzena yenitalu Coq. to this list. 

 Because of the confusion between Pyrausta penitalis and Py'rausta 

 ainsliei and the impossibility of finding from the literature the ex- 

 act source of the material from which the parasites were reared, it 

 is possible that not all of these species attack the true Pyrausta 

 penitalis. Panzeria penitalis, for one. is known to be a parasite of 

 Pyrausta ainsliei, and there is no definite record of its ever having 

 been reared from lotus-feeding larvae. All of these records should 

 be verified in the light of our more exact knowledge of their hosts. 



HYMENOPTEROUS PARASITES. 



Among the hymenopterous parasites, Bracon xanthostigma Cress. 

 is listed by Eiley and Howard {Ii.,p.J^39) as a parasite of this borer on 

 lotus at St. Louis, Mo. Viereck {11, p. 223) lists Meteorus commu7iis 

 Cress, with the simple statement that it parasitized P. penitalis. Hart 

 (6', J)- 180) mentions one secondary and two primary parasites, but 

 without determinations. We recognize at least one of his parasites, 

 the braconid, making white cocoons singly on the leaf surface. (PI. 

 Ill A.) This one, determined as Apanteles harti Vier. by A. B. 

 Gahan, was found to be the most common at Kimberlin Heights. Its 

 small white cocoons (1.5 by 4 millimeters) are firmly fastened to the 

 leaf disk either under the webbing or exposed outside. In July they 

 were only occasionally seen, but by early September were much more 

 common and were killing from 10 to 25 per cent of the larvae. This 

 species evidently attacks the smaller larvae and completes its life as a 

 parasite when its host is scarcely more than half grown. None of 

 them developed from larv^se larger than this. From T to 10 days 

 elapsed between the spinning of the cocoon by the parasite and the 

 emergence of the adult. 



Another parasite, very likely the other mentioned by Hart {6, p. 

 181), which the writers found only a little less common than the fore- 

 going, is an undescribed, yellowish brown species of Microbracon (de- 



