186 NE^Y YORK STATE MUSEUM 



wings hyaline, small crossveins not darker than the adjacent 

 veins, not clouded with brown, third vein i^eyond its middle 

 slightly bowing toward the costa ; length 2.5 mm. Male. Flag- 

 staff, Arizona. New Jersey (Johnson). 



Thalassomyia frauenfeldi Schiner 

 Theobald in "An Accoiiut of British Flies," p.202, reproduces 

 a note of Mr Swainson, which reads in part as follows : 



"... I found this larva several times on Obelia zoophytes 

 growing at the end of St Anne's pier. Next I found it on some 

 Coryne from the Mumbles (Swansea) and more recently I dredged 

 it from fifteen fathoms otf Spanish Head (isle of Man) adhering 

 to seaweed. Professor Miall, of Leeds, to whom I sent specimens, 

 thought it would ultimately turn out that Johnston's o m p o n - 

 t i a was Schiner's Thalassomyia frauenfeldi. This 

 seems very possible, as the descriptions are very similar. . ." 



The figure given bj" Theobald (1892) is reproduced on pl.34, fig.l. 



Genus 38. Chironomus Meigen 

 Illiger's Magaz. 2:260. 1808. (Chironomus, part) 

 Larva. The larvae of this genus differ from those of the other 

 genera of the group Chironomus primarily in the form of 

 the mouth parts, and are known as bloodworms; some species, 

 however, have pale larvae. The antennae are short, with the 

 first joint nearly twice as long as the remaining four taken to- 

 gether. Set on the end of the first joint, there is, besides the 

 second joint an unsegnuented appendage. On the under surface 

 of the labrum are several pairs of setae and sometimes a pair of 

 fan-shaped organs, perhaps sense-organs. The epipharynx is well 

 developed, and on each side of it is a long ( hitinized, sickle- 

 shaped ])rocess, which are called the lateral arms in the following 

 descriptions (pl.22, fig.lO la. and pl.2:{, tig.lO Ir). At the anterior 

 margin of the epipharynx is a minute comb with caudad pro.iect- 

 ing teeth (pi .23, fig. 10 c) ; caudad of these is a horseshoe-shaped 

 piece with the open end projecting cephalad (fig.lO). Within 

 this arch are several curved pectinate setae, which may be erected, 

 though they are usually folded down as shown in the figures. The 

 maxilla has, l)esides tlie rather iirominent palpus, some cephalad 

 projecting filaments on the outer lateral margin and a number of 

 setae, papillae and filaments on the inner margin (pl.22, fig.l nix). 

 The eleventh abdominal segment has usually though not always 

 two pairs of blood gills Iw^sides those on the twelfth segment. 



