222 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



discal venules either situated nearer tlie base of the wings than usual, either forming a quite regular 

 curvilinear line (siihrotutd and <iiit(!vitfa), or the hinder venule is decidedly bent inward (lii/dromeli 

 and Kniroloi-) or regularly curved inward (hiumhitn). 



Legs rather stout, with thick, long tufts of scales; fore tibite with flat spreading tuft; hind 

 tibia' with two pairs of large, nearly ccjual, long, sharp spurs. Abdomen long, cylindrical, not 

 tufted at the end, nor densely woolly, as in Cerura. 



Coloration : The species are quite variable, but more or less dull gray, with indistinct scalloped 

 transverse lines and an obscure linear or a twin discal spot; hind wings gray, with a faint interrupted 

 ditfuse outer line, or whitish; in the tmbrotata group the fore wings are pale ash, with tawny 

 blotches at the base, and ditt'used over the wing, while the dark markings are more distinct. 



The genus is characterized by the unusually short hind wings, with their well-rounded apexj 

 the front of the head is rather narrow, the palpi stout and usually broad; the thorax very hairy 

 beneath. The species are nearer those of kScliizura than any other gcnns of the family, showing 

 no near relationship to Cerura in adult characters, except the width of the head on the vertex. 

 The limits of the genus are doubtful, and some authors may in the future decide to divide it into 

 several, pei'haps retaining Lochina'us and Cecrita as genera. I have been inclined to do this both 

 from the venation and the larval characters, but when we take into consideration the unusual 

 amount of individual variation in the venation such a course seems hazardous. If any division 

 were to be made it must be to retain Lochmwus for a single species, mantco. 



The genus may be divided into five subgenera, which are, however, more or less artificial, and 

 appear to be perhaps incipient subgenera the I'esult of the specialization of the type in different 

 directions. 



Subgenus 1, Foro wingu long, apex squarish; hiud wiags well rouudeil; iu the hiud wings the second 

 subcostal venule arising huK way between the subcostal and independent H, (Lochmaua) manteo 



Subgenus 2. Fore wings rather long, apex pointed; hind wings rounded, short; palpi not very thick and 

 stout; fore wings gray, with olive-green or reddish tints, and obscure scalloped inner and outer lines; 

 discal mark diftuse and indistinct; discal venules in both wings forming a regularly curved line. 



II. (Cecrita) iimbrala, ohliqiia, astarte, guttiiillu, biundala, and phimosa 



Subgenus 3. AntenuiC with longer pectinations than iu the other species: fore wings short, broad and S([\iare 

 at the apex (subrotata and hiiilromcU); venation variable, the discal venules together forming an oblique 

 curve. Kiibrotala 



Subgenus 4. Discal venules forming a rather sharp angle directed inward, aud situated between the inde- 

 pendent venule and the first cubital venule. Female antenna- nearly as well pectinated as in the male. 



II. (Lilodonln) hi/dromeli 



Subgenus 5. Fore wmga moderately long, with the outer edge bent, the fore wings very uniform iu color, 

 and without distinct markings of any kind; venation nearly identical with that of astarte and obliqua. 



H, unicolor 



The generic characters of TAtodonta given by Harvey were these: "It differs by the antennae 

 being pectinate in both sexes. 'The thorax is more brushily tufted behind ; the head more appressed ; 

 the abdomen shorter." It seems to us that these characters are not of generic value, as //. tiuhroiuta 

 is very near II. hydromeli, but others may prefer to retain the genus as distinct, at least until 

 something is known of the larval history. 



Larva. — Body usually thickened in the middle; head with a red lateral band edged with white 

 or with white and yellow, with equal red lines, the space between clear green, or tilled in on first, 

 third, aud sixth abdominal .segments with red, which in some species extends down on the side; 

 amil legs either nornud or long and slender. In Stage I larva either normal, unarmed, or with 

 from one to nine pairs of deer-like antlers; anal legs with normal or (H. unicolor) with long, 

 slender, eversible ends. 



Cocoon. — Regular oval, translucent, like very thin parchment in color and structure: spun 

 between leaves. 



I'ujya. — Body usually thick and plump; front of head with two parallel, slightly marked ridges 

 between the eyes; cremaster armed with two stout, large, conical spines, differing much in shape 

 iu the different species. 



Geographical distribution. — The genus is confined to the New World and the species range from 

 Nova Scotia and Maine to Mexico, Central America, Surinam, and Brazil. At present more species 



