A SUGGESTION FOR THE PTEROPHORIDAE. 39 



Owing to this exceptionally favourable condition, the multiplication of 

 the insect could proceed at an extraordinarily rapid rate. In 1898, 

 therefore, the little moth appeared in great swarms. 



Now the fructification of Sorbiiii aiicuparia, and also that of 

 Pnmm padus, failed almost completely this season everywhere in 

 Finland. Since the insect could not obtain its ordinary food, the egg- 

 laying females instinctively Avent over to the apple trees. The apples 

 oiler plenty of nourishment, and while one mountain;ash berry 

 ordinarily harbours only one caterpillar, several of them can find an 

 abundance of food in a single apple. On account of this, many — I have 

 found as many as 25 specimens in a single rather small apple — cater- 

 pillars are often to be found in the same fruit. From this fact, and 

 considering the manner in which the caterpillars work, it will be 

 evident that the injury caused by Ari/i/resthia conjuiidla is much more 

 destructive than that of the common Codling-moth, Triipcta 

 pnmnnella, L. 



[ The change of food-plant here noticed is exceedingly interesting. 

 We do not seem to have any records of the larvte of Ariii/n'i^tliia 

 conjiif/cUa feeding on apple in th8 British Islands. Apple, however, is 

 a very possible food-plant for the members of this genus, and one 

 British species, An/i/rrsthia ciirvella, is attached to this food-plant. I 

 find that almost all the specimens of the latter species in my cabinet, 

 were taken on the trunks of apple trees in Westcombe Park. — J. W. T.] 



A Suggestion for the Pterophoridae. i llhistratcd Inj Plate.) 



By HAERISON G. DYAR, Ph.D. 

 The phylogeny of the Pterophoridae given by Mr. Meyrick 

 {Hand. Brit. Lep., p. 430) can be very easily tested by larval 

 characters. The PternpJwridae have an excellent series of characters 

 in their larvae, but these have not been brought out in their various 

 descriptions. I can only suggest to students of British larvte to 

 prepare full descriptions of all the species in accordance with the sug- 

 gestions here given, especially of the genera Psebtnphorii.'^, Stenoptiba, 

 and Ai^iliatis. O.ri/jitilK^ has the same structure as Triclnqitihn^, and I 

 have not made a figure of it on the plate. 



In America only about 26 per cent, of the Ptcmidtoridar are known 

 in the larval stage, and as it will probably be long before many are found, 

 it seems that this problem can be solved more quickly in England. 



Below are the principal characters to be noted, given in tabular 

 form : — 

 I. — Warts present — hair tufts instead of single tubercles. 



1. — Secondary [i.e., single, scattered) hairs also present. 



Warts i and ii united Type 1, Tl. I., Fig. 1. 



2. — No secondary hairs, though small secondary warts 

 (iii a, iii h, or both iii a and iii h) may be 

 present. 



n.— Warts functional Type 2, PI. I., Fig. 2. 



6.— Warts degenerate Type 2, PI. I., Fig. 3. 



II. — Warts absent — primary hairs single. 



1. — Secondary hairs present, iii a sometimes more 



distinct than the others Type 3, PI. I., Fig. 4. _ 



2. — No secondary hairs, all tubercles primary . . Type 4, PL I., Figs. 5,0. 



It is probably unnecessary to add that Type 1 is the highest, and 

 Type 4, the lowest, in degree of specialisation. 



