A. S. Packard, Jr. on certain Entomological Speculations. 215 



of any special "lands for the secretion, other than those emptying into 

 the mouth ; or to seek for special outlets on the " general surface of the 

 body" of the larva, proposes what might be well termed "The 

 Walshian theory of the Smearing and Daubing process observed in 

 the Construction of the Cocoons of all Cecidomyia /"* 



One scarcely knows at what point to attack this theory, so "utterly 

 anomalous" are the author's premises, and so strange his conclusions. 

 When it comes to this, that such gentle, quiet natures, as those of 

 the immature Gall-fly, assume suddenly the fierce brusqueness of the 

 Bombardier beetle, (Brachinus), and by a sudden discharge of its 

 pent-up gases — from what secret reservoirs, our author deigns not to 

 point out to us — blows out like a bubble, the mass of viscidity about 

 it. we actually doubt whether our author in discussing this point, has 

 shown his usual acumen, or better, we will "get over the difficulty by 

 supposing some abnormal affection of the larva," p. 566. "j" 



Our observations on the cocoon of an undescribed species of Ceci- 

 domyia, which closely resembles in its habits C. pint inopis of Osten- 

 Sacken, and which transforms on the terminal shoots of the common 

 yellow pine (Pinus rigida) lead us to agree with Harris, that the thin> 

 exceedingly delicate cocoon is spun, being neither exuded other than 

 through the mouth, nor a true puparium formed by the old larva skin. 

 We have before us several cocoons which have been soaking several 

 days in alcohol. The pitch has dissolved off, leaving a thin, delicate 

 cocoon, like tissue paper, and in all respects closely resembling the 

 thin cocoons of Pelopoeus and many other hymenopters of the families 

 Apidse, Andrenidse, Vespidae, and Ichneumonidae. 



We therefore fail to deduce the conclusion that the embryo of the 

 Katydid is not worm-like, because it is not, owing to the form of the 

 Ion" - , slender egg itself, curved within the egg. 



The fact that most lepidopterous larvae are " worm-like," seems to 

 follow from the reasoning of our author, who states that they are 

 curved upon themselves in their spherical eggs. Twice, on pp. 233 



*"I believe that it is in this manner that the pupal cocoon of all Cecidomvia 

 is formed, i. e. that it is not spun by the larva, but secreted in a glutinous form 

 from the general surface of its body." L. c. p. 560. 



f'Froin the careful study of the phenomena presented by the cocoons of the 

 Willow Gall-gnats, I have arrived at the conclusion, that after secreting the 

 glutinous matter from the general surface of their bodies, they must then dis- 

 charge something of a gaseous nature probably from the same pores which se- 

 creted the glutinous matter, so as to detach the adhesive material from their 

 external integument, and blow it up into a kind of bubble. We know that the 

 imago of the Coleopterous Brachinus has the power of discharging a very acrid 

 gas from its anus, and that most plant-feeding Heteroptera in all their states 

 discharge a fetid gas from a large opening like a spiracle on the inferior sur- 

 face of their bodies." L. c. p. 565. 



