46 EEPOET 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



The false feet or prolegs, Plate YI, Fig. 2, of which there are five pairs, 

 the first pair considerably smaller than any of the others, as is well 

 known, differ entirely from the true, anterior or permanent legs. They 

 are thicker, cylindrical, and one-jointed j they have a few long hairs, and 

 are armed with a row of a dozen and a half curved hooks. The hooks 

 turn towards the median line of the body j they diTninish in size from the 

 center of the row towards each end. Each hooif consists of a more 

 cylindrical, large basal portion, which appears to be chiefly imbedded 

 in the flesh of the foot, and a recurved hook proper, Plate I, Fig. 3, 

 which has a very thick cuticula. There is also a pigmented pad, which 

 lies over the base of each hook on the inside of the foot. We could find 

 no certain evidence of a second row of hooks such as have been de- 

 scribed in many caterpillars, though possibly there are very small claws 

 on the pigmented pads above described. 



The markings, colored stripes and dots, that decorate the larva, are 

 produced by various means, partly by deposits in the matrix of the 

 crust (epidermal cells), partly by colors of the crust itself. The dark- 

 brown color belongs to the crust, and is peculiarly distributed in a man- 

 ner that has not, so far as we are aware, been described hitherto. Upon 

 the outside of the crust is a very thin but distinct layer, which in cer- 

 tain parts rises up into a great number of minute, pointed spines that 

 look like so many dots in a surface view, Plaje YI, Fig. 8. Each spine is 

 pigmented diffusely, and together they produce the brown markings. 

 The spines are clustered in little groups, one group over each underly- 

 ing matrix, or epidermal cell. 



The stigmata of the larvae are small vertical fissures on the sides of 

 the segments. The first, fourth, and subsequent segments have each a 

 pair, making nine in allj there are none on the second and third rlags. 

 Yiewed from the surface they are seen to be provided with an anterior 

 lip, which is simple, and a posterior lij), which bears a projecting lever. 

 Both these lie quite deep down and serve to close the trachea. Above 

 each lip are several rows of hairs that are short, branching, and spine- 

 like. The stigmata form the subject of a recent excellent memoir by 

 Oskar Eiancher,* a pupil of Rudolph Leuckart, the distinguished pro- 

 fessor of zoology at Leipzig. On pages 543-546 of this essay the stig- 

 mata of caterpillars are fully described. According to Krancher, the 

 lever bearing, or posterior, lip is more developed than t^e anterior. 

 (The former was named by Landois the Verschlusshilgel, the latter the 

 Verschlusshand ; but these names are not specially appropriate, and we 

 prefer to use anterior and posterior lip instead.) The lever arises from 

 the upper end of the posterior lii^. In most of the diurnal lepidoptera 

 it is a simple chitinous rod, but in some of the Bombycidse it is more 

 complicated. Attached to the lever is a double muscle; one part, run- 

 ning to the lower end of the lever-bearing lip, serves to approximate 



* Oskar Krancher. Der Ban der Stigmenbei den Insekten. Zeitschr. f. wiss. Zoologie, XXXV, 1881, 

 pp. 505-575, Taf. XXVni-XXIX. 



