THE CANADIAN ENTOMOLOGIST. 299 



not occur. In the more generalized larvae, tubercles iv and v occur side 

 by side, in line, neither one higher than the other. In certain Tineids 

 this position begins to fluctuate, in some iv being a little higher than v. in 

 others v a little higher than iv. In the Bombycid phylum (culminating in 

 Noctuidse and Arctiidae), the tendency of iv to be elevated is emphasized, 

 and it rises as high as the top of the spiracle, or even a little above it, on 

 certain segments of some Noctuidae, while v remains in its original 

 sub ventral position. Mr. Tutt accepts this interpretation, and does 

 not feel called upon to invent hypothetical seta? to account for the change 

 in position of tubercle iv. Now, in the Sphingidae the tendency of v to be 

 elevated is emphasized, while iv remains in the original subventral 

 position. The dorsad movement of v in the Sphingidae is not greater, 

 not so great, in fact, as that of iv in the Bombycid phylum, yet here 

 Mr. Tutt finds a difficulty, and wishes to regard v as absent and 

 represented by a new seta. This seems to me a gratuitous assumption, 

 intrinsically improbable, and contradicted by the very palpable homology 

 of the primary Lepidopterous setae. Mr. Tutt would homologize "the 

 so-called" tubercle v of the Sphingidae (page 367) with "the prespiracular 

 wart of the Lachneids." This wart is secondary, as shown by my figure 

 of Tolype (Proc. Bost. Soc. Nat. Hist., XXVII., 144, 1896) and Mala- 

 cosoma (Psyche, VII., 259, 1895), Dut ^ ls accompanied by other 

 secondary structures, while the primary tubercles are all accounted for. 

 He can hardly really mean this, as he does not draw the obvious 

 inference of a close relation between the Sphingidae and Lachneidae. 



Mr. Tutt's references to the Lachneid tubercles are far from clear. 

 He says that in Pachygastria trifolii (p. 23), " iv and v form a 

 subspiracular, many-haired wart," and of Lasiocampa quercus (p. 60), 

 "iv + v almost postspiracular." This would imply a union of tubercle 

 iv and v, which I have never observed in the Lasiocampid phylum. 

 These tubercles remain separate, but become reduced, while the large 

 lappet is formed from tubercle vi. It is unfortunate that Mr. Tutt 

 did not bring out clearly the complicated but pretty homology of 

 the Lachneid warts. Figures would have been useful here. 



Finally, a word on the relationship of Dimorpha ( Endromis) and 

 Chelepteryx (p. 230). My own view is that these forms are nearly 

 related, though I have not the material to prove the point. It is 

 true that the mature larvae look very unlike, one being a smooth Sphinx, 

 the other a big, hairy Lasiocampid. But these characters are only 



