TABANID^ OF OHIO. 11 



nent, the proximal joint projects forward so that the large distal 

 segment is carried before all the other mouth parts. 



The rear of the head is usually referred to simply as the 

 occiput, near the middle of which the head is joined to the thorax, 

 a narrow strip lying above this junction is sometimes referred, 

 to as the nape or cervix. The cervix in this species is quite ob- 

 viously bounded by sutures. 



Head of male. The head is larger and approaches nearer 

 to hemispherical than in the female. The eyes are continuous 

 for a long distance and thus the front is divided into two parts 

 called the vertical and frontal triangles. The former is very 

 small and is bounded above by the vertical margin and bears no 

 ocelli or simple eyes in this species. The latter is limited below 

 by the antennae and includes the subcallus. Because of the in- 

 creased size of the head the antennae appear to have their union 

 higher up. 



The face in this sex is different than in the female. The sides 

 or cheeks are about in the same plane with the surface of the eyes 

 while the median part is much depressed. The mouth parts also 

 dififer ; the mandibles are entirely lacking and some of the other 

 parts are noticeably reduced. The second joint of the maxillary 

 palp is smaller and shorter than in the female, and turns upward 

 to lie against the face. The uppermost greenish band of the eye 

 is abbreviated outwardly and just above it, next the frontal tri- 

 angle, is the division between the lower area of small facets and 

 the upper area of large facets of which the eye is composed. On 

 the outer and upper margin of the eye the area of small facets 

 is extended to where the- eye meets the verticle triangle. 



Thorax. The three primary divisions of the thorax are not 

 easily separated, but the mesothorax comprises nearly all the space 

 visible from above, including the posterior, somewhat triangular 

 portion called the scutelhiin. 



The prothorax is small but is easily" located from the fact 

 that it bears the anterior pair of legs. A small lobe of the pro- 

 thorax, easily distinguished by being lighter in color, is closely 

 applied to each anterior corner, or humerus of the mesothorax. 

 Lying between the attachment of the anterior leg and the hume- 

 rus are two small prominences and just posterior to these lat- 

 ter is the anterior thoracic spiracle which marks the beginning 

 of a suture, the dorso-plenral suture, which passes backward 

 through the attachment of the wings, and ends beneath the front 

 edge of the scutellum. 



The dorso-pleural suture marks . the division between the 

 superior and lateral parts of the mesothorax, known respectively 



