1911] Aldrich — North American Species of Hydropliorus 55 



Hydrophorus agalma Wheeler (fig. 12). 



Male. Occiput rather coppery green, with one pair of post verticals; postorbitals 

 about a dozen, descending about a third of the eye-height; beard white, abundant 

 and long, no black bristles under the neck; the eye meets the mouth, so there is no 

 cheek; front opaque whitish in side view, but coppery with light from behind; 

 face wholly white poUinose, palpi of same color, with white hairs; antennae small, 

 of ordinary form. Thorax with strong coppery reflection on the disk, mostly outside 

 the dorsocentrals, a dark line in front on each side of the acrostichals. The 

 acrostichals and dorsocentrals are very small in front, but black; hindmost ones very 

 large; scutellar two pairs, large; humeral two, small; notopleural one; pleurae 

 densely whitish pollinose; propleura with two tufts of long white hairs, one above 

 the other, but no black bristle; sternopleura on the upper part with some scattering 

 very long white hairs; pleurae otherwise bare; metapleura just in front of the 

 halter with a peculiar protuberance, almost hemispherical; halter yellow with 

 brownish root. Front coxae whitish pollinose, with abundant long white hairs 

 in front and no black spines; front femur tapering, below with a row of short, 

 blunt spines extending nearly to the middle, about eight in number; front tibia 

 rather straight, with a row of slanting black spines on the front (outer) side, and on 

 the inner a very close row of minute black spinules, rather erect, ending at the tip 

 with two larger small spines; the tibia has on the outer side two or three regular 

 rows of pale hairs; middle femur with a row of long white hairs or bristles on the 

 lower side; the middle tibia and tarsus are rather short, and the last joint of the 

 latter is flattened and black; middle and hind legs provided with an unusual 

 amount of fine white hair. Wings unspotted, rather broad, slightly infuscated, 

 the veins broadly yellow at base, alula with a conspicuous fringe of white hairs, 

 first posterior cell considerably narrowed at tip. Abdomen with a dull coppery 

 reflection, the hairs all white and very long on the sides near the base. Hypo- 

 pygium bulky, but mostly concealed. Length, 5.2 mm.; of wing, 4.9 mm. 



Female. The pollen of the body is a little yellowish, and the face is decidedly 

 yellow; the front femur below has an irregular double row of spines, 25 or 30 in 

 all; all the spines of the front tibia are larger; no white bristles imder the middle 

 femur; middle tarsus normal; sides of abdomen with shorter hairs. Length, 5 mm.; 

 of wing, 5.3 mm. 



Three males and two females, collected by me at Battle Creek, 

 Mich., in the summer of 1897; Professor Wheeler's types were 

 out of this lot. 



The species has many interesting points of resemblance with 

 canescens, but also has easily discerned differences. 



Hydrophorus aestuum Loew. 



Hydrophorus eldoradensis Wheeler. 



Male. The whole insect covered with whitish pruinosity, less dense on the dor- 

 sum, which shows a little metallic color. Occiput with only two postverticals, and 

 only six to nine postorbitals on a side, extending only about a third of the way to 

 the mouth; beard white, no black bristles under the neck; cheeks hanging down as 

 a vertical flap below the eyes, which is short antero-posteriorly; face very wide. 



