— 173 — 



knowing the larval habits imperfectly, how the fly can possibly deposit its 

 egg upon the moth larva, as it lives continuously, as I suppose, within 

 the pitch. There must be some means of obtaining air and possibly 

 there are openings left for that purpose; I have not been successful in 

 finding out how the matter is managed. The' pupa-cell is covered at the 

 outer extremity by a thin layer of rather brittle pitch; it may be a fact 

 that this is sometimes destroyed when the temporarily exposed inhabitant 

 is victimized. Had the parasite occupied the body of the host since the 

 previous summer, it seems that the latter would have been too much ex- 

 hausted to have completed its transformations. But why guess out the 

 history of this parasite and its relation to the host? Now that its existence 

 is known of, the facts of its history may be readily determined. 



Prof. Riley had been very much interested in the paper. He could 

 not recollect any instance where the larval life has been so long, and the 

 /Egeridae as a rule are supposed to require only one year to undergo 

 their transformation. As to the manner in which the Tachina reaches 

 the /Egeria larva, it is probable that the latter must come to the surface 

 rather often to expel the excrement from its burrow and the Tachina 

 could take advantage of that. Once fastened, the egg is very secure. 



Prof. Lintner asks whether the larva feeds on the pitch. Dr. Kelli- 

 cott says that the excrement is mixed with pitch, but the larva makes 

 regular burrows in the wood and undoubtedly feeds upon the wood. He 

 says the larva is always more or less coated with pitch, and when remov- 

 ed from its burrow dies in a short time from the stiffening of this sub- 

 stance. He assumes that the larva must come out sometimes for air, 

 but does not see that there is any arrangement similar to that of Pcedisca 

 Scudderiana which has a little trap-door-arrangement which it can open 

 at will. 



Prof Lintner says that Nephopteryx Zhnmermani, or Pinipesies has the 

 same pitch pine feeding habit and also lives in turpentine exudations. 



Dr. Kellicott has observed this larva also which however does not 

 make so large an excrescence. The excrescences are also more irregular, 

 often a mere line or track of pitchy exudation marking the track of the 

 larva from whorl to whorl or twig to twig. This larva when removed 

 from its burrow also lives but a short time, owing to the hardening of 

 the pitch. 



Dr. Kellicott then read a paper 



ON THE PREPARATORY STACKS OF AN 

 UNDETERMINED COSSUS. 



This short paper on the preparatory stages of an undetermined 

 Cossus although in a somewhat unfinished state of preparation is presented 



