1017.] 181 



Saunders, in liis ' Hemiptera-Heteroptera of the Britisli Islands,' pnb- 

 lislied in 1S92, represents § A. montandoni Horv., and tlie accompan^'ing 

 description is that of the same species. No British examples of the true 

 A. aestivalis Fabr. are known, and our only species should therefore 

 stand vmder the name of A. montandoni Horv. As A. aestivalis has 

 Ijcen taken in France, it may yet be found in Britain, and I therefore 

 a])pend a table of the most easily recognizable differences between the 

 two species : — 



A. aestivalis Fabr. 

 i. Colour flavo-testaceoiis, more or 

 less variegated with I'lisco- 

 testaceoLis. 



ii. Abdomen equally contracted in 

 front and behind. 



iii. Dorsal genital plates of J ex- 

 tending considerably beyond 

 angles of preceding segment. 



A. montandoni Tiorv. 

 i. Colour blackish fuscous except the 

 bead and metanotum and some- 

 times parts of the pronotum, 

 which are stramineous. 



ii. Abdomen more contracted in front 

 than behind. 



iii. Dorsal genital plates of 5 "ot; or 

 very slightly, extending beyond 

 angles of preceding segment. 



No macropterous form of A. montandoni is yet known, though both 

 forms occur in A. aestivalis. It may be mentioned here that our British 

 specimens are rather larger than the Continental examples of the same 

 species ; ours measure 10 mm. in length by 7 mm. in greatest breadth, 

 whereas the measurements given for Continental A. montandoni, and 

 borne out by specimens in the British Museum, are 8^-9 mm. in length 

 by 6|-7 mm. in breadth. 



Ussing, in a report recently issued from the Freshwater Biological 

 Laboratory at Lyngby, Denmark, has given some interesting particulars 

 about the life-history of A. montandoni. He found the species in the 

 estuarine waters of the Gudenaa, near the town of Randers, which is at 

 the head of the Randers Fiord, and he observed that the eggs are laid, 

 generally u'regularly, upon the shells of several species of Mollusca, 

 especially Paludina vivijjara, Cardiiim, Scrohicularia, and Tidlina. 

 In the case of the bivalves, they weye found only on dead shells, and 

 alwa^'s on the outer surface of these. The eggs are regularly oval, 

 yellowish, and covered with a network of hexagonal cells. They are 

 laid about midsummer, although some that were kept in an aquarium did 

 not hatch till the end of September or the beginning of October. Larvae, 

 however, were found in March and May, from July to Seiitember, and 

 again in November, while imagines were met with in Ma}', and from July 

 to October. The larva differs from the brachypterous imago chiefly, 



