HARDWICKE'S SCIENCE-GOSSIP. 



55 



England and Scotland ; local. Length 2S lin. ; exp. 

 36 lin. 



^. horcalis (Zett). Dr. Hagen's description of 

 this species is as follows : " Brown, thorax with two 

 small bluish lines in front, and two narrow bluish 

 bands at tlie sides ; abdomen slender, cylindrical, 

 coarctate behind the base in the male, spotted with 

 blue (5), or yellowish (?) ; accessory membrane of a 

 uniform cinereous ; anal appendages of the $ long, 

 leaf-like, their end pointed, an inconspicuous basal 

 tubercle beneath ; the lower broad, triangular. AL. 

 borealis is easily recognised, because it is the only one 

 of which the subnodal sector is simple " (see fig. 32), 

 "and not bifurcate at the end ; the subnodal sector 

 is the fifth longitudinal nervure from the costa, 

 counting that as one, in the end of the wing. Habitat 

 Scotland. A single male in the cabinet of M. de 

 Selys. Length 26 lin. ; exp. 34 lin." 



-^. J2tiicca (Linn.). Wings clear, costal nervure 

 ochreous ; pterostigma black in $ , rather ochreous in 

 2 ; accessory membrane blackish, growing lighter 

 towards base ; thorax blackish ( s ), more brown in ( 9 ), 

 with two nearly straight yellow stripes in front, 

 interrupted in the 2, and two sloping yellow bands 

 at the sides j abdomen slender and cylindrical, con- 

 tracted near the base, more especially so in the 5 ; 

 colour ( f. ) black, with two blue spots on each segment, 

 and yellow markings at joints of segments ; in the 9 

 brown, with similar spots in yellow, and similar 

 yellow markings ; and appendages long and leaf- 

 shaped, ends pointed. British Islands generally^ 

 Length 32 lin. ; exp. 46 lin. 



^. cyanea (Miill.). Wings clear, costal nervure 

 brownish externally, pterostigma short, black in 5, 

 ochreous in 5 ; accessory membrane short, white ; 

 thorax in both sexes brown, with two large oval 

 yellow green spots in front ; sides yellow-green, 

 divided by dark lines ; abdomen slender, cylindrical, 

 sharply contracted near the base in the 5, in which 

 sex the ground colour is blackish-brown, with two 

 green spots dorsally on each segment as far as the 

 seventh, and bme spots on the remaining segments 

 and apex, as also all along the sides of the abdomen ; 

 in the $ the spots are all yellow-green ; anal append- 

 ages of 5 long and leaf-shaped, the ends turned 

 inwards. British Islands generally ; common. Length 

 32 lin, ; exp. 46 lin. 



AL. grandis (Linn.). Wings clear, of a transparent 

 red-brown tint ; nervures ruddy ; accessory membrane 

 opaque white ; pterostigma red ; thorax red-brown, 

 with two yellow bands at the sides, no markings in 

 front ; abdomen cylindrical, contracted near the base 

 in the $ (only) ; colour red-brown ; markings, four 

 blue spots at base of wings, two oblique yellow 

 stripes and two blue spots immediately following, 

 common to both sexes ; the 5 has the remaining 

 segments marked at intervals with blue ; the $ no 

 further marking. British Islands generally. Length 

 32 lin. ; exp. 44 lin. 



yE. rufescens (Van der Lind.). Wings clear, rather 

 i-ed-brown in tint ; accessory membrane large, dark- 

 tinted ; pterostigma ochreous ; thorax brown, with 

 two yellow bands at the sides, none in front ; abdo- 

 men cylindrical, contracted near the base in the 5, 

 brown, with a single conical yellow spot dorsally 

 near the base, the remainder unspotted, in both 

 sexes ; anal appendages of 5 long and leaf-shaped. 

 Local in the south of England. Length 30 lin. ; 

 exp. 40 lin. 



B. Anal angle of hind wings rounded in both sexes. 



Genus Aiiax (Leach). 



A.formosus (Van der Lind.). Wings clear, broad > 

 accessory membrane dark in the narrow part, white 

 at base; pterostigma very narrow, dark in 5, 

 ochreous in 2 ; thorax bright green ; abdomen rather 

 broad and depressed, contracted in 5 near the base ; 

 colour bright blue with a dorsal black pattern ; anal 

 appendages of the male more spatula-shaped, trun- 

 cated at the apex. Local in the south of England ; 

 occurs near Bournemouth. Length 34 lin. ; exp. 

 46 lin. 



Note. — Fig. 32 — Reference-letter C omitted in 

 figure : should be inserted over the black spot 

 towards the upper tip of the wing ; c. (triangle) in 

 figure should be c; D is the post-trigonal space. 

 The figures 27, 28, 33 & 34 are not mine, and were 

 doubtless inserted from a friendly wish to enliven a 

 dry description of species ; but I am bound to anti- 

 cipate probable criticism by remarking that the 

 venation of wing in fig. 27 is very hazy, while that 

 of fig. 28 is altogether erroneous. 



(71? be contiiuicJ). 



A FEW REMARKS ON GNATS' EGGS. 



WHILE examining some water from a pond 

 containing Plumatella, &c., I observed a 

 small round transparent ovasac (fig. 40) the like I 

 had not seen before. It contained more than 300 

 eggs, one of which I have shown enlarged in fig. 41. 

 I placed the ovasac in one of my shallow cells, 

 anxious to witness the hatching out of the eggs. 

 The ovasac was a quarter of an inch in diameter and 

 so perfectly transparent that every egg could be dis- 

 tinctly seen and the young creatures within them. 

 Two red eye-spots were visible (fig. 41 ci). I could 

 observe little or no motion in the egg. In about four 

 days some of them had escaped from the egg, 

 leaving a perfectly transparent shell. As soon as they 

 were clear of the shell, they elongated to three times 

 the length of the egg, in the form of fig. 42; they were 

 perfectly naked at first, and moved very quickly, 

 throwing and wriggling themselves about violently 

 in a figure of S fashion, and endeavouring to escape 

 from the ovasac into the surrounding water. This they 

 ultimately accomplished ; then they formed a gela- 

 tinous tube open at both ends, wherein they dwelt, 



