186 ' XKW YORK statp: .museum 



wings hyaline, .small c-rossveins not darker than the adjacent 



veins, not elouded with brown, third vein beyond its middle 



slightly bowing toward the costa : length L'.") mm. Male. Flag- 

 staff, Arizona. New Jersey ( Johnson i. 



Thalassomyia frauenfeldi Scliiner 

 Theobald in "An Aeeonnt of liritish Flies," p.202, repi'oduces 

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



"... I found this larva several times on Obelia zooj^hytes 

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

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

 it from fifteen fatiioms otL Sitanisli He;id (Isle of Man) adhering 

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

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

 t i a was Schiner's T h a 1 a s s o m y i a frauenfeldi. This 

 seems very possible, as the descrii»tions are very similar. . ." 



The figui-e given by Theobald (1S!)2) is reproduced on i>l.M4, fig.l. 



Genus 38. Chironomus Meigen 

 Illiger's Magaz. 2:260. 1808. (C h i r o n o m u s , part) 

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

 genera of the grouj» Chironomus primarily in the form of 

 the mouth jjarts, 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 unsegmented ap})endage. On the under surface 

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

 fan-shaj-ed organs, perhaps sense-organs. The epipharynx is Avell 

 deve]o[;e(l, and on each side of it is a long chitinized, sickle- 

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

 descriptions (]d.22, fig.lO la. and ])1.2."), tig.lO Ir). At the anterior- 

 margin of the epijtharynx is a minute comb with caudad jtroject- 

 ing teeth ( pl.^v), tig. 10 c) ; caudad of these is a horseshoe-shaped 

 piece Avith the open end i)rojecting cephahul (fig.lO). Within 

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

 though they are iisually folded down as shown in the tigures. The 

 maxilla has. besides the rather ]trominent jialpus, some cephalad 

 jtrojecting filaments on the outer lateral margin and a. numl>er of 

 setae, pajjillae and fllaments on the inner margin ( pl.22, tig.l nix). 

 The eleventh al)dominal segment has usually though not always, 

 two pairs of blood gills besides those on the twelfth segment. 



