184 NEW YoitK STATI: MrsF.r.M 



1. Thalassomyia obscura Johannsen 

 1903 Thalassomyia Johamisni. N. Y. State Museum bul. 68. 437 



Larva. The eggs were not found. The larva is 8 to 10 mm. in 

 length when full grown, pale or \ellowish green iu color, iis 

 head is dark bro\\n and lic;i\ily rliiliui/.cd. The head is some- 

 what longer than wide, the dorsal siiinre \\ell marked. Two setae 

 are placed immediaiely in from of the iransverse suhire. and at 

 the a]ical end of the labrum are two more. The lateral arms of the 

 ventral surface of the labrum are rather sliori ami si out, and some- 

 what pointed. The .-interior ventral margin of the lahrnm is provided 

 with short lleshv lilamenls instead of.setae as is usuallv the case in 







C h i r o n o m u s. The antennae are small. the l>;\sal joints about 

 four times as long as \\ide. each with i\\o terminal pieces, one of 

 which is four-jointed, the other simple. The mandiMe is about 

 twice iis long us broad, \\iih li\e blunt teeih; articulated at the 

 base is a long slender process with four terminal spines. The 

 maxillae are short prut uh.-iviices. covered with pointed projec- 

 tions, with a very short palpus with its terminal papillae, and 

 two stout setae projecting ventrad. The hypopharynx is tongue- 

 like, with two long basal pieces. Its apex and its dorsal surface 

 are covered with pointed papillae; vent rally there is an open 

 arched rib. At the cephalic en 1 of the ventral sclerite. and coales- 

 cent -\vith it. is the labium. with 11 blunt marginal teeth, the 

 middle one wide and broadly truncated. On the prothoracic seg- 

 ment are the two prolegs. each with about :;o long curved spines, 

 and a number of short and very small spines on the ventral sur- 

 face. At the base is a single slender seta, on each side a little 

 dorsad of the lateral line are two more, and candad of these and 

 "below the lateral line a group of three. The eleventh segment is 

 without blood gills; the twelfth with two comparatively short 

 legs, each with a crown of 8 to -10 bifid claws; on the dorsal sur- 

 face are two small protuherences upon each of which is a tuft of 

 five or six long setae. Ilet ween the legs and projecting candad 

 are four short blood gills. 



Pupa. The pupa is about 4.5 mm. long, with the colors of the 

 adult. It is much shorter in comparison to its breadth than is 

 C h i r o n o m u s . The wings extend to a little beyond the pos- 

 terior margin of the second abdominal segment. Eight segments 

 are present besides the short anal segment. On the dorsum of 

 each segment, toward the caudal margin, is a transverse band of 

 stout black bristles. Each band is composed of five or six rows. 

 The most caudad of these rows contain the longest bristles. 

 The anal segment is composed of two small lobes, each with a 

 single apical bristle. After two to four days of pupal life it 

 transforms into the imago. (See pl.50 in X. Y. State Mus. 

 Bul. 68.) 



