AEDES CAXADENSIS 651 



basal truncated coue. Basal appendages small, approximated, bearing four 

 email setas at tip. 



Larva, Stage IV (see figure of entire larva, plate 61). Head broad, nar- 

 rowed before eyes but nearly straight, a slight notch at insertion of antennae, 

 front margin broadly arcuate. Antennae rather long, slender, subcylindrical, 

 tapering a little distally, well spined all over ; a large tuft before middle ; four 

 spines of irregular lengths at tip and one small digit. Eyes large, transverse. 

 Both pairs of dorsal head-hairs and anteantennal tufts multiple. Mental plate 

 triangular, the central tooth scarcely longer than the others, eleven side teeth, 

 becoming more remote and larger toward the base except the last, which is small. 

 Mandible quadrangular, elongate, rounded without, with a group of blunt 

 spinules toward base ; two filaments near tip ; an outer row of stout cilia ; eight 

 filaments and two plumose hairs on outer edge; dentition of three teeth on a 

 prominence and a fourth rudimentary ; a long filament before, an appressed tooth 

 at base, a broad filament and five fringed ones within ; process below furcate, with 

 groups of hairs; basal prominence large, rounded, with five filamentous hairs 

 within ; ten large hairs at base. Maxilla elongate, hemispherical, divided by a 

 band-shaped suture ; inner half hairy on margin and near the suture ; a crown 

 and short band of hairs at tip ; outer half haired toward base, two filaments near 

 the suture and a spine near tip; palpus with wide base and four minute digits 

 at tip. Thorax rounded, wider than long; hairs abundant, not long, the sub- 

 dorsal prothoracic hairs single. Abdomen rather stout, anterior segments 

 (Shorter; hairs moderate, the laterals of first segment multiple, double on second 

 to fifth segments, single on sixth; secondary hairs few, but subdorsal tufts on 

 fourth and fifth segments rather long. Tracheal tubes broad, band-shaped, 

 slightly expanded in the segments, narrower posteriorly. Air-tube stout, 

 tapered, thickest beyond base, three times as long as wide ; pecten reaching nearly 

 to middle, the teeth evenly spaced; single tooth a long spine with wide base, 

 simple or with two to four branches. Lateral comb of eighth segment of many 

 scales in a triangular patch; single scale elongate with pointed base, fringed 

 with spines of which the apical ones are longest. Anal segment longer than 

 wide; dorsal plate large, reaching two-thirds way down the sides, straight on 

 lateral margin ; dorsal tuft a brush and hair on either side ; a single lateral hair ; 

 ventral brush well developed, with short tufts preceding barred area toward 

 base. Anal gills moderate, ensiform, about as long as the segment. 



Egg (plate 146, fig. 682) . Subfusiform, slightly flattened on one side, micro- 

 pylar end roundedly flattened, with a central truncated prominence ; sculpture 

 roughly quadrangular, the rows somewhat spiral. 



The larvae live in temporary ground-pools of all sorts. The eggs lie on the 

 ground over winter, and many hatch with the melting snow, making an early 

 spring brood. Many of the eggs, however, still remain, and in favorable loca- 

 tions some of them hatch -wath each rain, producing successive broods of adults. 

 Probably in the main there is but a single generation in the year, although this 

 is mostly inferential, as the point has not been proved. The species is one of the 

 commonest in the northern woods, and the adults are in evidence until later in 

 the season than the other early spring species. It becomes less prominent in tlie 

 south. In Virginia we have met with the larvae in cold springs; it is not 

 usually found in the ordinary ground-pools, as these are apparently too warm. 

 Prof. J. B. Smith of Xew Jersey has published the following observations : 



" This is the earliest and latest of the species that winter in the egg stage : 

 earliest as to both adult and larva, and latest as to larva only. The extreme 

 records for either direction are from Mr. J. Turner Brakeley, who found 

 recently hatched larvae in November and again in the February following. That 



