MEMOIES OF THE NATIONAL ACADEMY OF SCIENCES. 21 



The tbllowiug table is lui attempt at a olassiticatiou of some of the struetiiies arising from 

 the various modifications of the primitive piliferous warts or tubercles commou to uearly all, if uot 

 all, smooth-bodied lepidopterous larvae As is well kuowii, the term '-hair'' does not i)roperly 

 apply to the bristles or hair-like structures of worms aud Arthropoda, as mor[)hologically they 

 are not the hoinologues of the hairs of mammals, but arise, as Newport lirst showed, through a 

 modification and hypertrophy of the nuclei of certain cells of the cuticle. Hence the word seta, 

 as suggested by Laukester, is most applicable. 



A. — TrBEI!CLKS. 



a. Simple mid iiiiiiiitt; due to a sliijlit thickening of the hyporlermis and a deciiled thickeuiuLt of the over- 

 lying cuticle; the hypodcrmis coutains a large uuicellular gland, either for the seuretiou of the seta or for the 

 production of poison. 



1. Minute piliferous warts. (Most Tineid, Tortricid, aud Noctuid larva'.) 



2. Enlarged smooth tubercles, bearing a single seta. (Many Geometrid aud Jiondjycine larv:p.) 



3. Enlarged spherical tubercles, bearing a number of setsB, either radiated or sul>verticillate. (Arctians, Lithosiaus., 



Zygivnid.'p, inclndiiig some Gl.aueopinib.) 



4. High, uiovalde, smooth tubercles, having a terrifying fnnction. {Schizura, Xyliiiodes, Xotodonia, Xerice.) 



5. Low and broad, rndimeut.ary, replacing the "caudal horn." (Chirrooampa, the European I'heosiu dictaa, aud 



(licttroiih'S.) 



h. More or less spiiiiilosc or Kpini) (disappearing in some .Sphinges after Stage I). 



1. Long aud slender, usually situated on top of the eighth abdominal segment, with microscopic spiuules in Stage I. 



(Most Sphiugidiv aud Sesia.) 



2. Smooth subspherical warts. (Zygamida', e. g., Chalcosia. E.ast Indies) ; or elongated, but still smooth. (JItaciis 



atlas, and a species from Southwestern Territories. V. S. A.) 



3. .Subspherical or clavato spiny tubenles of many Attaci; the spiuules usually short. 



4. Spiuulated spines or elongated tubercles of Ceratocamipda' aud Heniilucidie. (//. io aud 77. maia, etc.^ 

 .5. .Spike-like hairs or spines. {Samia cijiithia, Auisot.a, East Indian llypsa, Anagnia.) 



6. Antler-like spines. Early stages of Heterocampa bhiiidata, gutlirilfa ami ohliqna.) 



B.— Set.e ("Hairs," Biustles, ktc). 



1. Simple, fine, short or long, microscopic or macroscopic set;e, tapering hairs, scattered or dense, often forming 



pencils. (JIany Bombyccs, Zyga'uida-, Noctuo-bombyces, Apatelie ) 



2. Glandular haii-s, truncate, spnidle-shaped or forked at the end, and secreting a more or less viscid fluid, i Mauy 



m Stages I and II of Notodontians, many butterfly larvie, and in the last stages of Pterophoridic-.) 



3. Long, spindle shaped hairs of Apatelodes, Apalela americana, figured in Harris Corr., PI. Ill, fig. 2; also Packard's 



Guide, fig. 23G, and the European Tinolius ebiirneiffutta Walk. 



4. Flattened, triangular hairs in the tufts or on the sides of the body of Gastropachu americana, or llattened, spindle- 



shaped scales in the European G. quercifolia.' 



0. Spiuulated or barbed hairs. (Most Glaueopides, etc., Arctians, Lithosiaus, aud Liparid*. and many other 



Bombyc.es.) 



C. — PsECnO-TfBEROLE.S. 



1. The filaraeutal anal legs (stemapoda) of Cerura and Heterocampa mnrihesia. 



2. The long suraual spine of Platyjitericida'. 



THE USUAL POSITION OF THE MORE SPECIALIZED WARTS, HUMPS, OR HORNS. 



Everybody has noticed that the horn characteristic of larval Sesiie and Sphinges is uniformly 

 situated on the back of the eighth abdominal segment and uo other, and that when it is absent, 

 as in Chcerocampa, etc., it is replaced by a small, low, and flattened tubercle, the segment itself 

 being somewhat swollen. The larval Agaristidie (Alypia, Eudryas, Copidryas, Psychomorpha, 

 etc.) have a prominent, gibbous hump on this segment, or at least this segment is more or less 

 prominent and humped, not only in this family, but also in certain smooth-bodied Noctuida-, as 

 Amphipyra. and Olyfim remicolor, etc. 



In many Notodontida' the first abdominal segment bears a conspicuous hump, sometimes 

 forked, often ending in a seta. 



In the larval Ceratocampida^, either the prothoracic segment or the second and third thoracic 

 segments bear high conspicuous horns and spines. They may be roughly classified as follows: 



1 See my article in Annals and Magazine of Natural History. Ser. G. ix. jip. 372-373. 1892. 



