216 BRITISH ENTOMOSTKACA. 



Genus 4 — Alteutha.* 



Cyclops, Baird, Mag. Zool. and Bot., i, 1837. 

 Alteutha, Baird, Trans. Berw. Nat. Club, ii, 155, 1845; 

 Ann. and Mag. Nat. Hist., xvii, 416. 



Character, — Eoot-jaws small, simple ; body flat. Two 

 strong falciform appendages from the fifth segment of the 

 body. 



1. Alteutha DEPRESSA. Tab. XXX, figs. 1, 2. 



Cyclops depressus, Baird, Mag. Zool. and Bot., 331, t. 10, f. 9-12, 



1837. 

 Alteutha depressa, Baird, Trans. Berw. Nat. Club, ii, 355, 1845 ; 



Ann. and Mag. Nat. Hist., xvii, 416. 



The body is depressed, flat, and broad, difiering in this 

 respect very much from all the other genera described. 



The thorax is composed of four segments, the first of 

 which contains the head consolidated with it, and is much 

 the largest, being more than equal to the three succeeding, 

 and having the upper part projecting in a short obtuse 

 point. 



The abdomen consists of five segments, and is about 

 one third the length of the body ; the terminating seg- 

 ment having on each side a small lobe, from each of which 

 issues a moderately long seta. 



The eye is situated rather lower down than usual in the 

 other species of this family, and is of a fine ruby colour. 



The antennae are short, strong, subcylindrical, setiferous, 

 and divided into six or seven articulations ; the first three 

 of wdiicli are the largest, the last four being smaller and 

 shorter. In the female we find a lateral ring at the junc- 

 tion of the fourth and fifth joints. The swelling, in the 

 male, is situated in the foiu'th, followed by the hinge-joint, 

 and terminated by a hook. The antennules are of two 

 articulations, the latter being terminated by four short 



* "Alteutha," the Town of the Tweed. 



