28 CONNECTICUT GEOL. AND NAT. PIIST. SURVEY [Bull. 



found in any famil}^ of Diptera. The binodo-^e condition occurrino^ in 

 the individual antennal segments of certain cecidomyids makes it very 

 difficult to determine the exact number of segments in the extremely 

 delicate antennae of these insects, but in the tipulids it is quite easy to 

 distinguish the segmentation of the antennae, and the amount of var- 

 iation found in the tipulids, ranging from the maximum of 39 seg- 

 ments found in Cerozodm to a minimum of 6 segments found in He:c- 

 atoma, compares rather closelv with that recorded for the cecidomyids 

 by Felt. 



The antennae furnish excellent taxonomic characters which are 

 much used in the classification of the Diptera, but there is no general 

 agreement concerning the proper application of some of the terms 

 employed in referring to the parts of the antennae. Thus, the word 

 "joint", in the strict sense of the term, should indicate the membran- 

 ous articulatory region which is usually devoid of bristles or setae. ; 

 so that it is quite inaccurate to speak of the bristles, etc., borne on the , 

 '•joints" of the antennae, and it is preferable to refer to the region be- 

 tween the joints as a segment. 



In all other groups of insects, the first, or basal, segment of the 

 antenna is called the scape, and the second segment is called the pedi- 

 cel, but dipterists frequently misapply the term "scape" to the two 

 basal segments of the antemiae, although there is no reason why they ; 

 should not be as accurate as other taxonomists in this respect. The ; 

 third segment of the antenna is called the postpedicel in lower insects, 

 and it constitutes the first segment of the fi^agellum, or ]3ortion of the 

 antennae distal to the second segment (pedicel) in these forms. Hen- 

 del (1928), however, would make the three terms postpedicel, funic- | 

 ulus and flagellimi, synonymous with designations applied to the en- j 

 tire antenna distal to the pedicel, leaving no term available for the ' 

 true postpedicel, or third segment, although such a designation should \ 

 be very useful in such Diptera as the Cyclorrhapha, etc., in which the \ 

 three basal segments form most of the antennae, and the latter usage \ 

 has been adopted here. 



In the higher Diptera, the segments distal to the third segment, 

 or postpedicel, are so greatly reduced that the portion of the antenna 

 Avhich they form appears to be merely a slender appendage of the 

 trimerous antenna. When this appendage is slender and flexible, or 

 bristle-like, it is called an arista. The arista may be dorsal, if it is 

 borne on top of the third segment, or it may be sub-basal, if it is 

 borne near the base of the third segment, or it may be terminal or 

 apical, if it is borne at the tip of the third seirment. The arista may 

 be bare, plumose, pectinate, etc., according to the occurrence and ar- 

 rangement of the hairs, etc., it bears; and the character of the arista 

 has considerable classificator}' value in some groups of higher Diptera. 



When the reduced segments distal to the third segment form a 

 stouter and more rigid appendage, it is called a style ; and the style is 

 always terminal. Unfortunately, the term, styli, is applied to the , 

 styliform abdominal appendages of lower insects, and according to f 

 some investigators certain of these styli are supposed to form the 

 distal portion of the forceps, or claspers, of male insects: and in tlie 



