43 



Semiothisa califormata, no Phmiane orillata, no Thnmnonoma guenecria, \i 

 would be rasy to define these genera, and separate llieni Iiy well-marked 

 characters; but the lowest species combine more or less I lie characters of 

 the drllerent genera, and the three groups seem to diverge from a Ibriu like 

 any one of the aliiivc-mcntioiu'd species. Such species are synth(;tic types, 

 coml)ininu the ciiaraclers ol' \\\c liirce genera to wiiic !i llii'y Ix'Ionir. It is 

 impossible to say which of tiie three genera is the higher. In liu't, they an; 

 souK^vhat parallel lornis, like the topmost l)ranclies of a tree. It is so with 

 tlie genera. Tluiiinionoina and Knjifrliid vary in dill'erent directions in one 

 or two or three ciiaracters, viz. in the. venation, in the form ol" the abdomen, 

 in the peripheral charact(Ms, aiid es|>ecial!y cognation. The gvuuti Eumacoria 

 is one of much interest, as. while closely allied to Sciiiiuth'im in its structural 

 features, it anticipates Eplouc in its general api)earance and markings, so that 

 it would l)e easily i-ei^arded as lieloni,nnu to IIk^ Kiinoni'iruc. 



It thus appears that tliei'e may l)e syntiietic types among species and 

 genera. It also appears that there may lie synthetic types lietweeii two fam- 

 ilies, such as Dori/oilcx iun[ Surlariop/tor// and Lig'ta. wliich are Xoctuids, with 

 some phaUenid characters. 



It is not improbable that these so-called synthetic or comprehensive 

 types are ancestral t()rms from which other species and genera have diverged. 



§ lo. — Mimicry of natural objects. 



No cases of mimicry of other insects, so far as I 

 am aware, are known to occur amonu: the larvjv or 

 imagines of this family. That, however, the geometrid 

 caterpillars closely resemble the twigs of the ])lants on 

 which they rest was noticed by Linuivus in the tenth 

 edition of" his " Sy.<tema Xatune." The most remark- 

 able example which has lidlen under my observation is 

 the larva of Dirpanodcs vitrus. (4. & 1\., which lives on 

 tin; stems of the jnni])i'r-l>nsli. The best desei'i[)iiou 

 that could !)e given of it is to say tiiat it would easily 

 be mistaken, as it holds itself straight out motioidess 

 by means of its anal legs, for a portion of a twig of the 

 tree on which it tceds. It is about an inch and a half 

 long, and less than a Hue in thickness. Its l)ody is (piite 





