THE COCCIDS OF GUERNSEY. 



BY MR. W. A. LUFF, F.E.S. 



The CoccidcB are popularly known as Scale insects and 

 Mealy-bugs. They belong to the Homoptera, a sub-order 

 of the Hemipiera. The females are invariably destitute of 

 wings and the mouth is formed for sucking the juices of 

 plants. The male is in some cases wingless but usually 

 has one pair of wings. The most curious fact about this 

 sex, however, is that they have no mouths, the place where 

 that organ usually is being occupied with one or two pairs 

 of eyes. 



Among the best known of the Coccids are the common 

 Mussel Scales, Mytilaspis pomorum, which infest apple and 

 pear trees. These scales are all females, and the male has 

 proved so extremely rare that until its discovery in England 

 by Mr. Newstead in 1896 it had remained unknown for 150 

 years. The female has a shield-like covering, under which 

 she lays her eggs ; she then dies and shrivels up, the shell 

 remaining attached to the plant until the eggs are hatched. 

 Many species of this family are remarkable for the number 

 of generations succeeding each other for years without the 

 intervention of a male. 



The Mealy-bugs are dreaded as a pest by horticulturists, 

 many of them being very common in hot-houses, &c. They 

 belong to the genus Dactylopius and cover themselves with a 

 white mealy substance, hence their name. 



Closely allied to this genus is that of Ripersia, most 

 of the members of which are of subterranean habits, living 

 on the roots of grasses and plants in ants' nests. The genus 

 Orthezia are easily distinguished from other Coccids by the 

 body being covered with thin plates of pure white wax, 

 which overlap and form beautiful and symmetrical designs. 



Although most of the Scale insects are injurious, three 

 species furnish us with commercial products of great im- 

 portance. 



