PARASITES OF LARGER BROWN-TAIL CATERPILLARS. 



301 



agement to the attempts which have been made, and which will be 

 renewed, looking toward the establishment here of others having a 

 somewhat similar distribution. 



Pales pavida (fig. 70) is perhaps as promising as any among these, 

 although it is possible that it appears so on account of a somewhat 

 larger knowledge which we possess concerning its life and habits. It 

 was first imported in not very large numbers in 1906. In 1907 about 

 as many were secured and colonized as of the successfully introduced 

 Zygobothria, and more were colonized in 1909. The fact that it 

 has not been recovered is by no means to be taken as positive asssur- 

 ance that it is not established, and it is well within the bounds of 

 possibility that it will be recovered in 1911 or 1912. 



It is one of the species 

 which deposits its eggs 

 upon the leaves to be 

 eaten by its host (fig. 36, 

 p. 214) and was the first 

 species having this habit 

 to be carried through all 

 of its transformations in 

 the laboratory. In 1908 

 Mr. Townsend succeeded 

 in carrying some of the 

 flies through the period 

 allotted for the incuba- 

 tion of their eggs, but he 

 did not succeed in secur- 

 ing oviposition. In 1909 

 Mr. Thompson had better 

 fortune, and not only se- 

 cured eggs in abundance, 

 but fed these eggs to a variety of caterpillars and secured either the 

 puparium or the fly in nearly every instance. He also secured much 

 interesting data upon the early stages, and upon the life and habits 

 of the early stages, a story of which is left for. him to tell. The 

 accompanying illustrations of the eggs and larvae were prepared 

 under his direction. That of the egg (fig. 3.7, ~b. p. 214) is of inter- 

 est in comparison with that of the egg of BlepJiaripa scutellata (fig. 

 37, a, p. 214), as showing the difference in the characteristic micro- 

 scopic markings. That of the larva will give a good idea of the 

 integument al "funnel" (figs. 71, 72), formed by the ingrowing epi- 

 dermis, as differing from the tracheal "funnel" characteristic of the 

 larva of Blepharipa, as figured on pages 215 and 216. 



Fig. 70.— Pales pavida: Adult female with front view of head 

 above and side view below, and antenna at left. Much en- 

 enlarged. (Original.) 



