g [Januarr, 



THE LIFE-HISTORY OF SCYMNUS CAPITATUS F. 

 BY GILBERT J. ARKOW, F.E.S. 



Although the little Coccinellid beetles of the genus Scymniis are very 

 numerous in almost all parts of the world and fourteen species are known 

 in this countrj^ scarcely anything seems to be recorded as to their life- 

 history, and I believe no figure of a larva exists except the extremely 

 crude representations by Reaumur of the *' herisson " or " barbet blanc " 

 which there is no means of identifying with any particular species. The 

 second name (meaning" white poodle") is quite appropriate, but the 

 soft wooll}'" covering does not produce the least resemblance to a hedge- 

 hog. Sharp, in the *' Cambridge Natural History," states tliat the lai'vae 

 of Scymnus have small depressions on the surface from which it has been 

 ascertained that waxy secretions exude. During the past summer I have 

 found larvae of Scymnus capitatus at Tooting, in company with Con- 

 wentzia jysociformis, upon oaks infested with Fhylloxera, upon which 

 both were preying. It is interesting to notice that the two predaceous 

 insects are both characterized by the property of exuding a waxy seci-e- 

 tion, the beetle in the larval, and the Neuropteron in the adult stage. 



In Scymnus capitatus the wax}^ substance forms a complete covering 

 upon the upper surface, the head and legs alone being without it, and in the 

 resting position these also are concealed by the projecting tufts. When 

 active the white masses upon each segment are separated just enough to 

 allow free movement to the body, although the movements are always 

 slow. After moulting, the animal is greyish and naked, but the secretion 

 begins to apj^ear again immediately. Seen without 

 its covering the larva resembles those of Coccinella 

 and Adalia, but is less tapering in form. The feeding- 

 habits are also practically the same. Fabre mentions 

 a '• barbet " of undetermined species which he found 

 on the ground beneath terebinth-trees, feeding upon 

 ApMdae fallen from above, but the one I have rejDre- 

 f^ ^"S^ sented here was invariably upon the leaves of oak. 



Larva of Scymnus The method of pupation is veiy peculiar. The 



capitatus, larvae fix themselves by the hind extremitv. as in other 



magnmed 7 diam. "^ . - . 



Coccinellidae, and in little groups of two or three, 

 generally in some hollow upon a slightly withered leaf. The body 

 becomes contracted and assumes a nearly circular shape, but beyond 

 this there is no apparent change, The cottony mass forms a complete 

 covering for the pupa as for the larva. The larval skin shrinks back 

 and leaves the pupal envelope applied closely to this protecting coat, 



