affecting the Potato-crops. 



101 



In the potatoes with the Acari were larvae of various little 

 beetles which assist in reducing putrid substances to a simple 

 state, which is indispensable fot supplying the soil again with the 

 proper elements as food for the support of vegetation. One of 

 them was very similar to the larvae of a beetle called Dermestes, 

 but only 1^ line long; another, a little larger, would undoubtedly 

 produce some beetle of the families Carabidce or Staphylinida?. 

 A somewhat similar larva was found in France, which Guerin 

 believes may belong to a Genus of little Rove-beetles,* called 

 Calodera.j Another kind was detected by M. Rayer, which is 

 likewise supposed to belong to one of the Staphylinidce. 



Nests also of little creatures were found in rotting potatoes, 

 which looked like black mites, but on close examination they 

 proved to be beetles — members of a Family entirely devoted to 

 the consumption of putrid animal and vegetable substances. I 

 allude to the Family Histerid^e; the species from the tubers 

 belongs to the Genus Abr^sus,{ and was named by Fabricius 



27. A. minutus. It is a little oval, convex, shining beetle, like 

 a seed, and not more than ^ a line long, often only \ : it is of a 

 dark chestnut colour : the head is bent down, the feelers being 

 visible but not the jaws, and in front are 2 short, curved, 

 11-jointed horns, terminated by a distinct somewhat oval club: the 

 eyes are small and lateral : the thorax is very broad and punc- 

 tured ; the scutel is invisible : the elytra are broad, semi-oval, not 

 covering the rump, beneath them is folded a pair of wings : the 

 6 little slender legs lie close to the body in repose ; the anterior 

 shanks are flattened, and the 5-jointed feet are short and very 

 slender. 



In the early spring these beetles are found under dung, and in 

 September 1 have observed them in ripe and decayed cucumbers 

 in frames, where sometimes they are generated in thousands, the 

 warmth favouring their increase. 



A still more minute beetle was detected amongst the potatoes, 

 called Trichopteryx rugulosa ;§ it is not larger than this dot . being 

 scarcely visible to the naked eye, nevertheless its pair of horns and 

 six legs are complete, and the beautiful wings with a long fringe 

 are most marvellously folded up under the wing-cases when not 

 in use. 



I have repeatedly found small Rove- beetles in the rotten 

 potatoes, where I expect they live upon the Acari and minuter 

 animals, but of this I have no evidence. Guerin likewise thinks it 

 probable that their larva? may live upon those found in the rotten 



* Vide Journal of Royal Agric. Soc, vol. iv. p. 126, pi. H. f. 28 and 29. 

 + Curtis's Guide, Genus 219 b . % Curtis's Guide, Genus 142, No. 2. 



§ Bull, des Seances de la Soc. Roy. et Cent. d'Agric, pi. 6, f. 3, and 

 Sturm's Deutsch Fauna, vol. xvii. pi. 320. 



