57 



strongly tapering at apex; on basal third a pecten, rather short with about fifteen 

 to eighteen thorns, the first of them without lateral thorns, the others rather broad 

 with four strong ones. The last two thorns large, detached, out of line and with a 

 much greater distance between than the others; a large tuft at middle of tube, 

 consisting of seven hairs. 



Anal segment longer than broad, covered by a rectangular plate, almost 

 reaching the barred area of the ventral brush; dorsal hair-tuft consisting of a coarse 

 tuft and two very strong and long hairs. Ventral brush in the barred area con- 

 sisting of about ten rays, each ray carrying about six or seven hairs, before barred 

 area six free hair-tufts; the lateral tuft consisting of one single hair; four gills, 

 equal, acute. 



Lateral tufts of labrum rather short, the inner part modified in comb-hairs, 

 arranged as a crown round the palatum; this is covered with short, soft hairs. 

 Mandibles quadrangular with two strong spines before collar; a row of short cilia 

 from collar and a row of strong spines, about ten, from margin. Dentition four 

 strong spines, the first much stronger than the others ; before them three long acute 

 dagger-like spines, one of them faintly dentated; a series of bristles below. Process 

 below distinctly divided with hairs on both apices; a group of hairs at base. Max- 

 illre elliptical, divided, by a suture; on the apex a long tuft of hairs and at its 

 base one or two short spines. The whole space between suture and inner border 

 covered with long soft hairs; long bristles along the inner border; between suture 

 and palpe an area covered with soft hairs. Palpe well developed with four digits. 

 Mentum triangular, an acute median tooth and from ten to twelve lateral teeth. 

 Colour commonly green, often milky, very transparent, the head also green, the 

 sipho yellowish-red. 



Systematical remarks. The description of the female and male is taken 

 from HOWARD, DYAR and KNAB (A. abftchii) with which my specimens have been 

 careful compared; they have been determined by Dr. EDWARDS. As far as I know r , 

 the species has hitherto not been described from Europe; most probably it is con- 

 cealed in one of the fairly numerous insufficiently described older species. With 

 regard to the imagines there is full accordance between the American specimens 

 and the Danish ones; with regard to the larva? there are some discrepancies. H. D. K. 

 (p. 690) indicate that both frontal tufts are double; in my larvae the lower frontal 

 tuft has always three or four hairs; further, the lateral hairs on the abdomen on third 

 to sixth segments are single in the American specimens, double in the Danish specimens. 

 Biology: In North Seeland we often find, on the plains in the forests or in 

 the outskirts of the wood, small ponds, the bottom of which is not decaying leaves, 

 but grass; the ponds are always extremely shallow and dry up in May, often before 

 other ponds are laid dry. They are almost always dry from May to January, 

 and the water these ponds contain is almost only melted snow; it disappears again 

 in the course of one or two months. In these ponds, the true habitats of Bran- 

 chipus Grubii and Limnetis brachyura, we find the above-named grassy-green Culi- 



I). K. D. Vidensk. Selsk. Ski-., naturvidensk. og mathem. Afd. 8. R.-ekke, VII, 1. 8 



