152 CHIRONOMID^:. 



fleshy leg on the under side of the first segment, which points 

 towards the head, and which it has the power of lengthening or 

 contracting. Its various serpentine contortions also assist it in 

 moving. When removed from the substance which constitutes its 

 food, it is enabled to regain it by leaping. Lying horizontally, it 

 brings the anus near the head, regulating the distance by the 

 length of the leap it means to take ; when, fixing it firmly, and 

 then suddenly resuming a rectilinear position, it is carried through 

 the air sometimes to the distance of two or three inches. It appears 

 to have the power of flattening the anal extremity, and even of 

 rendering it concave, by means of which it may probably act as a 

 sucker, and so be more firmly fixable." 



This genus may be divided into four principal groups : 



* Praebrachial areolet open. 



f Wings deflected. Antenna? of the male with thirteen joints, of 

 the female with seven joints. 

 J Antennae of the male feathered. Group 1. 

 jj Antenna? of the male with few hairs. Group 2. 

 ff Wings incumbent. Antennae of the male twelve-jointed, fea- 

 thered ; of the female seven-jointed. Group 3. 

 ** Praebrachial areolet closed externally. Group 4. 



The species of the first group may be arranged in the following 

 sections : 



A. Fore metatarsus longer than the fore tibia. 



a. Pore metatarsus twice the length of the fore metatibia. 

 b. Wings not spotted. 



c. Thorax black or grey. Species 1, 2. 

 c c. Thorax green, with three black stripes. Species 3-5. 

 c c c. Thorax green, with three testaceous stripes. Species 6-9. 

 c c c c. Thorax testaceous or green, not striped. Species 10, 11. 

 b b. Wings spotted. Species 12. 



a a. Pore metatarsus longer than the fore tibia by three-fourths. 

 b. Thorax black. Species 13-15. 



b b. Thorax green, with three black or brown stripes. Speciesl6-20. 

 b b b. Thorax green, with three testaceous stripes. Species 21-24. 

 a a a. Pore metatarsus longer than the fore tibia by two-thirds. 

 b. Wings not spotted. 



c. Thorax black, or grey. Species 25, 26. 



c c. Thorax pale, with three black or brown stripes. Species 



27-32. 



c c c. Thorax pale, with three luteous stripes. 

 d. Abdomen with black bands. Species 33. 

 d d. Abdomen without bands. Species 34-40. 

 c c c c. Thorax not striped. Species 41, 12. 



