8176 Insects. 



magnified). As Ratzeburg justly remarks, Dr. Hartig, in his Aderfl. 

 Deutschl. i. p. 184 and following pages, has not described the true 

 N. septentrionalis, Linn., as according to him, the female has red 

 femora. The imago is from 9 to 10 mm. long, expanding to from 12 

 to 13 mm. In the female the head and antennae, together with the 

 breast and base and apex of the abdomen, are black ; the mouth is 

 brownish and the cenchri white. Coxae black, but the ends of those of 

 the third pair and the apophyses are obscure while ; femora black, 

 those of the first pair inclining to brown ; the tibiae and tarsi of the 

 first and second pairs reddish brown, the tibiae with white rings at the 

 base ; the femora of the posterior pair are black, the tibiae white, the 

 end, which is black, being flattened and expanded, spines red, tarsi 

 black, the first joint being also broad and expanded. The second 

 and succeeding segments of the abdomen up to the sixth are red ; the 

 first has usually a narrow, red, transverse line on the anterior margin. 

 The wings are transparent, with a brown stigma ; costal nervures 

 brown, with a smoke-coloured band extending downwards from the 

 stigma, and faintly continued to the apical margin. The posterior 

 wings are also clouded between the anterior and apical margins (fig. 6). 



The male is distinguished by a more elongated form of abdomen; 

 the mouth is obscure brown, as are also the tegulae and the antennae 

 (the latter sometimes only on the under side, or for half their length). 

 In this sex the legs are almost entirely reddish brown, as only the 

 coxae for four-fifths of their length, the trochanters and apophyses of 

 the anterior and intermediate pairs of legs, as also the ends of the 

 femora, the apices of the tibiae, and the tarsi of the posterior pair of 

 legs are black. 



These insects saw an opening in the veins of the leaves of the 

 alder, and deposit as many as 150 eggs in rows. According to Ratze- 

 burg the larvae are also found on the birch, the broad-leaved willow, 

 the wild cherry, the hazel, and the balsam-poplar ; like DeGeer, I 

 have only found them in this country on the alder, sometimes in such 

 numbers that the whole tree was stripped of its leaves ; thus in 1811 

 solitary alders growing between Bodegraven and Sluipwijk, and rows 

 of the same tree thickly planted along the banks of the canal near the 

 Hague, were completely stripped of their leaves. 



At the time of quitting the egg the larva is white, with a brown 

 head, but by the following day has acquired a green colour. They 

 begin by eating out holes in the middle of the leaves. After the 

 second moult they are obscure green or pale brown, both extremities 

 being somewhat yellow, with two black stripes on either side ; the 



