MEMOIKS OF THE NATIONAL ACADEMY OF SCIEXCES. 21 



The foUowiug table is an attempt at a flassiticatioii of some of the structures arising from 

 the various moditications of tlie i)rimitive i)iliferoas warts or tubereles common to uearly all, if not 

 all, smooth-bodied lepidopterous larva". As is well known, the term '-hair" does not properly 

 apply to the bristles or hair-like structures of worms and Arthroixxhi, as morphologically they 

 are not the houiologiies of the hairs of mammals, but arise, as Newport Urst sh(jwed, through a 

 moditication and hypertrophy of the nuclei of certain cells of the cuticle. Heuce the word seta,, 

 as suggested by Lankestei', is most ai)i)licable. 



A. — TuDEItCLES. 



a. Simple and minute, duo to a slii^lit tliickeuiug of the liypoilenuis and a decided thickeiiiuj;- of the over- 

 lying cuticle; the hypodenuis contains a large unicellular gland, either for the secreliou of the seta or for the- 

 prodactiou of poison. 



1. Minute piliferous warts. (Most Tineid, Tortricid, and Xoctuid larva'.) 



2. Enlarged smooth tubercles, bearing a single seta. (Many Geometrid and Bonibycine larva>.) 



3. Enlarged spherical tubercles, bearing a number of sefce, either radiated or subverticillate. (.\rctians, LithosianSj, 



ZygienidiF, including some Glaucopina'.) 



4. High, movable, smooth tubercles, having a terrifying function. {Schi-uni, Xylinodes, Xotodoiita, Xerice.) 



5. Low and broad, rudimentary, replacing the "caudal horn.'' (ChaTocampa, the European I'heoaia dicttva, and 



dictaoides.) 



h. More or less spinnlose or spini/ (disappearing in some Sphinges after .Stage I). 



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



(Most Sphingida' and Sesia.) 



2. Smooth subspherical warts. (Zyg.Tnida-, e. g., Chalcosia. East Indies) ; or elongated, but still smooth. (Altacus 



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



3. Subspherical or clavate spiny tubercles of many Attaci; the spiuules usually short. 



4. Spinulated spines or elongated tubercles of Ceratocamipdie and Hemilucida'. {H. io and H. maia, etc.) 



5. Spike-like hairs or spines. (Samxa cijnthia, Anisota, East Indian Hypsa, Auagnia.) 



6. Antler-like spines. Early stages of Heterocampa biuiidata, guttiviita and obliqn<(.) 



B.— Set.e (" Hauls," Buistles, ?;tc.). 



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



pencils. (Many Bombyces, Zyga'nida-, Noetuo-bombyces, Apatehe ) 



2. Glandular hairs, truncate, spindle-shaped or forked at tUe end, and secreting a more or less viscid fluid. (Many 



in Stages I and II of Notodontians, many butterfly larvie, and in the last stages of Pterophorida?.) 



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



Guide, fig. 236, and the European Tinoliiis ehurneigulln Walk. 



4. Flattened, triangular hairs m the tufts or on the sides of the body of Cnistropaeha americanu. or flattened, spindle- 



shaped scales in the European G. quercifolia.' 



5. .Spinulated or barbed hairs. (Most Glaucopides, etc., Arctians, Lithosiaus, and Liparida', and many other 



Bombyces.) 



C. — FSEUDO-TUBEReLE.S. 



1. The filameutal anal legs (stemapoda) of Cerura and Heterocampa marthesia. 



2. The long suranal spine of Platyptericida'. 



THE USUAL POSITION OF THE 3I0RE SPECIALIZED WARTS, HUMPS, OK HORKS. 



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

 situated on the back of the eighth abdominal segment and no other, and that when it is absent, 

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

 being somewhat swollen. The larval Agaristid:e (Alypia, Eudryas, Copidryas, Psychomorpha, 

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

 prominent and humjied, not only in this family, but also in certain smooth bodied NoctuidiV, as 

 Amphipyra, and Olygia versicolor, etc. 



In many Xotodontida- the tirst abdominal segment bears a conspicuous hump, sometimes 

 forked, often ending in a seta. 



In the larval Ceratocampidi\», either the prothoracic segment or the second and third thoracic 

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



•See my article in Annals and Magazine of Natural History. Ser. 0. i.\. pp. 372-375. 1892. 



