262 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



dopterous larvae, and we have bred it from seven widely different species. (5) Spilo- 

 chalets mariw (Riley). This species, while parasitic on Thyridopteryx, is more partial 

 to the large silk-spinning caterpillars, as we have reared it from the cocoons of 

 all of our large native Silk- worms. (6) Pteromalus sp. This undescribed Chalcid is 



Fig. 100. — Pimpla conquisitor : a, larva; 6, head of do. from front; c, 

 pupa ; d, adult female (hair line indicating natural size) ; e, end of male 

 abdomen from above; /, same from the side — all enlarged. (After Riley.) 



found very abundantly in the Bags, but may be a secondary parasite. (7) Binocarsis 

 thyridopterygis Ashmead.* This parasite was bred from the bags in Florida by Mr. 

 William H. Ashmead, who believes it to be parasitic on the eggs. (8) Tachina sp. 



Fig. lOl. — Hemiteles thyridopterigis : a, male ; 6, female; 

 c, sack of bag-worm cut open, showing cocoons of parasite, 

 natural size. (After Riley.) 



We have bred a large bluish Tachinid from the bags. Its eggs are commonly at 

 tached to the bags externally, near the neck, and the young larvae, on hatching, 

 work their way into the case. They frequently fail, however, to reach the Bag- 

 worm, 



34. THE WHITE- SPOTTED TUSSOCK-MOTH. 

 Orgyia leucostigma (Abbot and Smith). 



The caterpillar of this moth is now and has been for some time a 

 most grievous pest in our cities. We have observed it on Boston 

 Common, where for years, as stated by the late Dr. Brewer, it has been 

 injurious to the elms, as well as the maples. Though the species ex- 

 tends from Maine and Canada to the Southern States, it is most abun- 

 dant in the New England and Middle States, and more common in 



*Mr. Ashmead's description (Canadian Entomologist, XVIII, No. 5, p. 97, May 

 (18d6), shows that this species can not belong to Dinoearsis, as limited by Mayr. 



