362 WILLIAM T. M. FORBES 



and when pectinate, with dorsum evenly scaled, with two widely over- 

 lapping rows of scales to a segment, often with only the tips of one 

 row exposed; when not pectinate, with base usually fully scaled, middle 

 of shaft with the outer w r horl of each segment continuous, and the inner 

 interrupted by a broad sensory area below; in both forms with most 

 of the swollen tip covered by a sensory area, which bears only scat- 

 tered scales. Maxillary palpi minute, of porrect type; tongue strong, 

 naked ; legs often with stiff bristly hair gathering in tufts at the spurs ; 

 sometimes with fine hair also. Fore wings (figs. 224-229) very nar- 

 row, with short outer margin, and well-marked anal angle ; often trans- 

 parent ; R 5 stalked or united with R 4 ; accessory cell and base of medial 

 lost; CUo arising well out toward apex of cell; anal region extremely 

 reduced, the anal veins weak or rudimentary. Hind wing usually 

 broader, but narrow ; more or less extensively transparent in our species, 

 often with only the margins and veins scaled; costal edge (fig. 223) 

 with Sc and R closely parallel, becoming coincident outwardly, and 

 bearing a series of recurved spines, which interlock with a similar 

 series on the inner margin of the fore wing. Cell usually squarely 

 closed ; anal region fully veined. Frenulum simple in both sexes. The 

 sex is most easily determined by counting the number of visible abdom- 

 inal segments, there being six in the female and seven in the male; 

 or by the larger male antennae. The body markings on the basal part 

 of the abdomen are usually alike in both sexes, but the last band 

 is very generally a segment farther toward the apex in the male than 

 in the female. Anal tuft always conspicuous in male, simple or rudi- 

 mentary in female. 



Egg of the flat type, oval. Larva (figs. 232, 233) white; without 

 markings; boring. Front nearly or quite reaching vertex; tubercles 

 usually moderate (obsolete in Melittia). Posterior addorsal setae on cer- 

 vical shield nearer middle line than anterior; abdomen with tubercles 

 i and ii separate, iv and v adjacent ; spiracle of eighth segment above 

 the level of the others; spiracles elliptical. Ventral prolegs with two 

 transverse rows of uniordinal hooks; anals with a single row. Pupa 

 incomplete, usually formed in the tunnel; with only a couple of basal 

 segments immovable, and even these loosening on dehiscence. Labial 

 and maxillary palpi exposed; tongue and antennas not reaching the 

 tips of the wings ; the antennas normally swollen toward tip ; prothorax 

 wider than dorsal head-piece. Last segment with ventral spines, but 

 cremaster not even represented by specialized setaa. Two rows of 

 spines to each segment dorsally. 



The connection of this family with the Yponomeutoidea is unmistak- 

 able but, at least as represented in the United States, it is clearly defined 

 both in adult and pupa. 



