Art. 23 GENUS CYLINDROMYIA MEIGEN ALDRICH 6 



ovipositing apparatus are in the male sex, as far as Imown, quite 

 within the range of the rest of the genus. Several species show in 

 the females some specialization tending toward a single holding 

 hook instead of a symmetrical pair, and this is more or less associ- 

 ated with the development of special groups of spines on the venter. 

 Attention is especially called to the remarkable condition in 7iana 

 Townsend, in which one of the hooks is weak at base and regularly 

 breaks off at an early stage in the activity of the adult female tly. 



As a detailed description of all the species would consist mostly of 

 unprofitable repetition, it is thought best to begin with the generic 

 characters (liberally interpreted) of the type species hrassieaiia of 

 Europe, taken from specimens identified by Professor Bezzi. After 

 the ke}^, each North American species is described only as far as the 

 characters seem important for separating the species from hrasslcana 

 or known North American species. By this method it is hoped to 

 save a good deal of space and yet omit nothing of significance. 



GeneHc characters of Cylindromym (from the type species) — 

 head in profile almost as long as high, from front a little wider than 

 high (length 39, height 42, width 51 units of micrometer) : the lower 

 edge long and straight, the back bulging, so that the bare eyes are 

 in profile about as far from the back edge as from the front; front 

 moderately wide, .30 of head width in both sexes; frontal stripe 

 broad, of uniform width to antennae, which are inserted above mid- 

 dle of head, moderately long, the arista bare, with distinct but not 

 elongated penultimate joint. Face not receding, slightly keeled 

 above, the epistoma jutting out between the vibrissae, facial ridges 

 bare. Paraf acials bare. Palpi generally absent, occasionally present 

 in a very rudimentary condition (in European material — I have seen 

 but one case in the American; strangely enough this variability 

 seems not to be even of specific value) ; proboscis slender but not 

 much elongated. A^erticals one large pair; ocellars one smallish 

 pair directed forward and outward, behind the ocellar triangle an- 

 other pair directed outward, and still another small pair behind these 

 on the occiput directed upward; two pairs orbitals in female, none 

 in male; frontals about eight, none of the upper distinctly larger 

 and roclinate, the lowest just at insertion of antennae, the row not 

 diverging toward the eye; bucca with only a single row of bristles 

 along lower edge, disappearing behind. 



Thorax rather narrow, barely as wide as the head, with promi- 

 nent humeri, the suture behind the middle. Postscutellum distinct. 

 Chaetotaxy: acrostichai 0, 0; dorsocentral 3, 3; humeral 2, and 

 numerous outstanding stout hairs; posthumeral 1; presutural 1; 

 notopleural 2; supraalar 1, stout; intraalar 2, only a little above the 

 preceding; postalar 2; scutellum with two stout lateral pairs and a 

 small decussate apical, no discal; sternopleural 2; pteropleural 0; 



