104 



a week. I have found as high as 45 per host. (In some Hj- 

 menoptera I have found several hundred per host. Once I 

 reared 338 from one larva of Megachile palmarum.) Pupation 

 takes place where the larvae have fed, and where they have 

 been numerous the pupae lie in a mass. The pupal stage is 

 about two weeks. 



Family Trichogrammidae. 



Pentarthron flavum Perk. — This tiny egg-parasite I have 

 reared from eggs of Vanessa tammeamea Esch., Deilephila li- 

 neaia Fab., Nacoleia accepta (ButL), Nacoleia hlachhurni 

 (Butl.), Nacoleia m-eyncl-i (Sw.), Archips ■postvittanus 

 (Walk.) and Amorhia emigratella Busck. From one to several 

 parasites develop in a single egg of the host, depending on the 

 size of the egg. From Nacoleia eggs I have had usually about 

 three per egg, while from the larger egg of Vanessa tammeamea, 

 24: emerged. This is a very beneficial parasite. It often de- 

 stroys a large proportion of the eggs of Nacoleia blachhurni and 

 Archips postvittanus, and recently Amorhia emigratella — many 

 egff-masses of the latter being found entirely parasitized. It 

 has a very short life-cycle. I bred a generation m 10 days. 



The eggs of Bactra straminea are also parasitized, and Mr. 

 Fullaway has bred it from eggs of Heliothis obsoleta Fab. 



Pentarthron semifumatum Perk. — Beared from eggs of Her 

 se cingulata Fab. (Fullaway). I have reared it from the egg of 

 Deilephila lineata. One one occasion I reared 7 of this species 

 and 7 of P. flavum from one egg of the latter. 



Family Ichneumonidae. 



Ichneumon I'oehelei Sw, — This parasite was introduced 

 from America by Mr. Koebele about 15 years ago. It parasit- 

 izes Cirphis unipiincta (IIaw\), the army- worm, Agrotis ypsi- 

 lon Rett., the black cutworm, and probably other related cater- 

 pillars, but does not accomplish much good, as it does not appear 

 to be very prolific. The parasite stings an egg into the cater- 

 pillar, where the egg hatches and the larva grows while the 

 caterpillar is obtaining its growth. The host is not killed till it' 

 enters the ground to pupate. ' The parasite finally transforms 

 to the adult within the host pupa, without spinning a definite 

 cocoon — merely spinning a little silk on the inside of the empty 

 pupa case of the host. The adult finally emerges by breaking 

 an irregular hole at the anterior end of the pupa case. 



