l36 THE entomologist's RECOf.D. 



ABBREVL\TIONS USED IN PLATE III. 



elongated spindle-shaped 

 leucocytes. 



basement membrane of the 

 larval hypodermis. 



middle membrane of the 

 larval wings. 



Grundmembran of Semper. 



nuclei of the stellate cells 

 that secrete the Grund- 

 membran. 



posterior. 



processes of young hypo- 

 dermis cells. 



scale. 



tubes prodnced from the 

 newly - formed Grund- 

 membran. 



trachea. 



On Lepidopterous larvae. 



By HAERISON G. DYAR, Ph.D. 



Mr. Tutt has requested me to point out briefly the characters of 

 Lepidopterous larvte that are the most valuable in their classification. 

 I have found these to consist in the positions of the tubercles or warts 

 from which the hairs arise, not so much in the ultimate structure of 

 the hairs, humps, horns, or other modifications. Considering only 

 the abdominal segments, there are in the simplest and lowest condi- 

 tion, five hairs on each side, each arising from a simple tubercle. 

 These are the five primary setje — i. or anterior trapezoidal, ii. or 

 posterior trapezoidal, iii. or supra-spiracular, iv. or posterior sub- 

 spiracular, and v. or anterior sub-spiracular. There is also a tubercle 

 on the base of the leg (vii.) which bears more than one hair, and a 

 single-haired one (viii.) on the inner side of the leg. This condition 

 may be found in the newly-hatched larvae of some species of all 

 families of the Lepidoptera, and also in the Mecoptera. In certain 

 groups there is further a tubercle (vi.), situated above the base of the 

 leg, which may appear after the first change of skin. I have called 

 this a sub-primary tubercle. All these tubercles may become many 

 haired (warts), or there may be developed more or less numerous hairs 

 from other parts of the surface of the body (secondary). 



The sub-order Frenat.i: (Comstock) divides into five great groups : — 

 I. — Butterflic'^.— In the first stage the primitive five setse are found. 

 Tubercles iv. and v. are in line, or iv. is moved upward somewhat behind 

 the spiracle. The principal characteristic of the group is that, after 

 the first stage, all the modifications of armature, hairs, etc., are 

 secondary, not corresponding exactly with the location of the primary 

 setae. II. — Sphimjids. — In this group the first stage shows the 

 primitive set«, but v. is very regularly moved up before the spiracle. 

 After the first stage, the setje are obscured by fine secondary hairs or 

 granules, somewhat as in the butterflies. III. - Soturnian.^. — In this 

 and the following groups, the mature structures are developed from 

 the primary tubercles, only in rare cases obscured by secondary hairs, 

 and even in these cases the original tubercles have a persistent cha- 

 racter, as shown by their appearance in earlier stages than the 



