7404 Insects. 



regard as an unknown genus of bivalve MoUusca , but on placing it in a bottle of water 

 the real nature of the creature becomes revealed ; it is an Enlomostvacon : as a whale 

 among minnows, so, said I, is my new genus among water-fleas ; but again I was mis- 

 taken. I had not fibbed long before I brought to light a veritable Apus or shield- 

 shrimp, and I saw at once that my supposed new genus was the young of it, thus 

 illustrating very prettily the law in the development of organized beings, that the tran- 

 sition state of a higher form will represent the permanent condition of genera lower in 

 the same class, for the Apodidse are justly regarded as the highest among Entomos- 

 traca. When I get on board I examine my captures with the valuable aid of my friend 

 Dr. Baird, or rather of his ' Monograph of Apodidae,' and 1 find they belong to Leach's 

 genus Lepidurus, which is furnished with a plate between the bases of the long caudal 

 filaments. I find, moreover, that my specimens agree exactly with the description of 

 L. glacialis of Kroyer, from Cape Krusenstern in North America : " The tail setae are 

 finely plumose, and the flap between them is of a somewhat square shape, short and 

 toothed on its edges." I cannot find any account of the metamorphosis of the Apodidae, 

 or whether it is known that in the young state the siiield is folded on itself longitudin- 

 ally in the form of a bivalve shell, which entirely conceals the head, body and feet of 

 the animal. There is but a single large black eye in these young ones, situated Poly- 

 phemus-like, in the middle of the forehead. The very young larvae are of a pale horn- 

 colour, and swim in a steady manner forwards, the ventral edge of the shell being 

 directed downwards. As they move through the water they partially expand 

 and close the valves of the shell. Older and larger individuals are olivaceous, and are 

 fond of lying on their sides in the sand at the edge of the pond, and now and then 

 spin round and round by means of their protruded tail. The adult of Kroyer's shield- 

 shrimp, as it may be called, keeps in deep water, and is voracious and predatory, not 

 confining his attention to small things in the water, but even feeding on drowned 

 dragon-flies.— .4r//iur Adams. 



Eggs of the Genus Colias imported in Clover (see Zool. 7359). — I have for many 

 years thought that the eggs of C. Edusa — the only species I have seen here — are 

 imported along with clover seed from the Continent, and which is sown every year all 

 over the Cotswolds. I can only account in this way for the appearance of this butter- 

 fly on our hills. My observations are chiefly confined to the neighbourhood of Ciren- 

 cester, where I have seen this insect occasionally, either by the road-sides or in the 

 garden, but not more than two or three in the season, until the year 1859, when they 

 appeared in great numbers. I remember, in a walk of four miles along one of the 

 loads which leads from Cirencester into the country, couating more than twenty, and 

 they were seen in other directions. The sides of our highways on the hills have 

 mostly been quarried, and in these spots a profusion of small flowers spring up, which 

 no doubt attract these butterflies from the fields where we may suppose they have 

 been bred. It is a beautiful and refreshing sight to see them pass and repass, and 

 alighting on the various flowers, quite undisturbed in their peaceful and happy enjoy- 

 ments. I think that all of those which I saw were males. I did hope, that having 

 appeared in such numbers and in so inviting a region, I should have seen some the 

 following year ; but no, not one was on the wing. This may be accounted for by the 

 extreme wetness of the season ; and I understand on the south coast of Devon, where 



