30 Mr. C. H. T. Townsend on Diptera 



on transverse suture, linear, extend from anterior margin of 

 thorax to transverse suture, are parallel, and divide the black 

 of mesoscutum in front of suture into three portions of 

 exactly equal width. Win.^s entirely black, except the hind 

 border, which is hyaline. Pulvilli pale yellowish white ; foot- 

 claws pale yellow, with black hooked tips (female). Halteres 

 pale yellowish, more reddish at base. The character from 

 which I have named the species, and which is so striking 

 that it will distinguish it at once, is the colour of the tegulae 

 and alulets. The tegulce (lower pair of scales) are large and 

 wholly of a deep golden-yellow colour, being very conspicuous 

 against the black of the body and wings, while the alulets 

 (upper pair of scales, appearing like an upper and smaller 

 pair of tegulffi), which cover the forward portion of the yellow 

 tegulje, are pure white on the anterior half and abruptly black 

 on posterior half (the wing being understood to be directed 

 backward in the usual position). Such a beautiful effect in 

 coloration of the tegulae and alulets 1 have never before seen 

 in any fly. 



jyote. — What I have called the alulets (the upper or 

 smaller pair of scales) are not true teguhe, but appear so 

 when the wing is flexed or directed backward in its usual 

 position. When the wing is extended strongly forward it is 

 seen that this smaller scale is a part of it, being borne on the 

 extreme base of the inner edge of the wing, proximad of 

 the alula, which in turn is proximad of the axilla (anal or 

 axillary angle) of the wing. It should be known as the 

 ahdet, which is the diminutive of alula. I. think that this 

 term is deserving of use and should be adopted. Beginning, 

 then, with the axillary angle of the wing, the latter being 

 extended forward to its utmost, and proceeding inward or 

 })roximad, we have in order the axilla, alula, ahdet, and 

 tegula. I remark here upon these ))oints of terminology in 

 detail, as no writer seems ever to have paid any attention to 

 the distinctions to be made in the application of the last three 

 of these terms. 



Since the above was written Dr. Williston has called 

 attention, in his new synopsis of Diptera just published, to 

 the fact that Osten Sacken has proposed the name " anti- 

 tcgula" for the upper pair of scales. I think " alulet" is a 

 preferable term, from the fact that it is a short word and has 

 long been in use, notwithstanding that it has been indefinitely 

 applied in some cases. 



While on the subject of Tricho'poda, I wish to propose the 

 name T. subalipes for the species described by me from Santo 

 Domingo under the name of T. subcilij^es (Journ. N. V. Eut. 



