34 MISCELLANEOUS PAPERS. 



the first three or four segments. They may be called prolegs, since they have the 

 parts necessary to such organs and, what is more, are used as prolegs. On the pos- 

 terior dorsal border of most of the abdominal segments there may be a narrow, 

 irregular, opaque marking of the same color of the narrow band in the region of the 

 prolegs; eighth segment on each side with two narrow, curved markings which have 

 the appearance of being composed of contiguous punctures. These markings are of 

 the same shade of color as the other darker areas, and the lower one is more than 

 twice as long as the upper. 



Pupa (fig. 8, c) 18 mm. long and 4 mm. in diameter. Light brown in color, thorax 

 somewhat paler than the abdomen. Antennal and other tubercles of the head and 

 thorax prominent and darker than the surrounding parts. Prothoracic spiracular 

 tubercle slightly elevated, reniform, oblique; rima uniformly curved for nearly its 

 whole length; but just before the anterior end the curvature is stronger, although no 

 hook is formed. First al)dominal spiracle nearly round; rima almost uniformly 

 curved, posteriorly very slightly widened just at the end, anteriorly slightly nar- 

 rowed and curved so as to form a short hook. The other abdominal spiracles agree 

 with the first one in general, l)ut there is slight variation in the enlargement and 

 curvature of the extreme ends. Terminal teeth (fig. 8, d) prominent, shining brown 

 in color, darkest at the extreme tips. Dorsal pair of teeth smallest and closer 

 together than the ventral, lateral teeth longer and larger than the ventral and located 

 much beneath the dorsal, in fact they are nearly midway between the dorsal and 

 ventral. 



THE BLACK HORSEFLY. 



{T<thainis uiratua Fabricius. ) 



The eggs of this horsefly — male and female adults of which are shown in 

 figure 9 — are placed in masses of various sizes on the leaves and stems of 

 grasses and sedges and other plants growing in marshy or wet ground, 

 but not necessarily in the water. A single mass may contain as many as 

 600 eggs, but often they are smaller and they may be largei-; they are 

 white when first placed, but soon turn brownish. The mass is very con- 

 vex and composed of several layers, one above the other, the bottom 

 layer being attached to the surface of the leaf or stem and the other 

 layers each to the one that was placed before it. Each agg is elongate 

 spindle shaped, between 2 and 3 mm. in length and narrowed at each 

 end. A female was observed ovipositing June 23 at 11 o'clock. The 

 eggs were taken and kept in a room out of the sun, where they hatched 

 on the morning of July 2 before G o'clock, thus requiring an incubation 

 period of nearly nine full days. It has been proven that the eggs of 

 tabanids hatch more quickly when exposed to the sun dui-ing the day, 

 as where they are usually deposited; therefore, the time given is proba- 

 bly too long for eggs under natural conditions. 



There is no definite way, so far as observed, of telling the eggs of the 

 black horsefly from those of other species of its genus, but being a 

 large species the masses are much lai-ger than in .some others, and are 

 more convex than usual. The particular place of oviposition is in a 

 measure characteristic. 



Larva?, when first hatched, are about 3 mm. in length, white, and with 

 a narrow darker shade at the union of each two segments. As soon as 

 they drop to the ground they begin to burrow and are soon beneath 



