A STRUCTURAL STUDY OF THE CATERPILLARS — 

 II. THE SPHINGIDAE. 



William T. M. Forbes, New Brunswick, N. J. 



This paper may be considered a continuation of that pub- 

 lished in the Annals of the Entomological Society of 

 America, III, 94-132, with plates 10 to 20. The references to 

 figures with the prefixed numeral I, refer to plates 13 and 14 of 

 that article. 



In the caterpillar stage the Sphingidae may be defined as 

 follows: With secondary hair on the body, epicrania, front, 

 clypeus, maxillae and labium, but never on the antennae or 

 distal parts of the maxillae and labium. There is almost 

 always secondary hair on the adfrontals. It is present on the 

 mandibles in Cressonia only, and the labrum bears a single 

 additional hair in Pachysphinx. Front not more than half the 

 height of the head (measuring here and elsewhere in this paper 

 from the base of the front to the vertex. The frontal punctures 

 are close together, and when distinct the primary setae are 

 somewhat further from them than they are from each other, 

 but they are distant from the outer edge of the front. The 

 lobes at the two lower outer angles of the front tend to be large. 

 Adfrontals not very wide, often narrow, not extending between 

 the clypeus and mandible when distinct in the lower part; 

 puncture a little below the upper seta. Clypeus narrow in the 

 middle, often grading into the membrane below. Labrum well 

 marked, often with very deep notch; vi distant from the margin, 

 and usually directly below ii. Mandible with a large scrobe, 

 bearing the two usual setae, one at the tip, and the other 

 about half way out, toward the posterior side. Antennae with 

 second joint most often twice as long as the first; the remaining 

 joints exceptionally minute. Maxillary palpi stout, the second 

 joint somewhat shorter than the first; submenta ill-defined, and 

 mentum broad at the base. Spinneret broad, flat and short, 

 with the usual three sclerites; labial palpi similar in form, and 

 set obliquely to it, forming with it a sort of scoop (which would 

 seem more useful in feeding than in spinning). 



Claws not distinctly notched, broadening abruptly at their 

 base. Prolegs with a double row of hooks, about 20 to 60 in 

 number; not very regularly arranged in Hemaris, etc. The 

 hair on the prolegs is never as rudimentary as higher on the 

 body. 



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