6 BULLETIN 730, U. S. DEPARTMENT OF AGRICULTURE. 



a beetle on the vines resembles more closely a small lump of brown 

 earth than any form of animate life. While collecting, the writer 

 has frequently mistaken them for the pellets of excrement dropped 

 by sphinx caterpillars on the grape leaves. When disturbed they do 

 not run or fly directly but leap to a considerable distance and either 

 take wing while in the air or fall to the ground, simulating death. 

 When caught and held closely in the hand they give forth a squeaking 

 note pitched on an exceedingly high key. This note is heard also 

 during sexual attempts of the male. 



FEEDING MARKS. 



The feeding marks on the leaves (PI. II, A) are situated on the 

 upper surface and extend only through the epidermis and paren- 

 chyma. Usually they are in the form of a slightly curved line, aver- 

 aging about 2 mm. long by 0.5 mm. wide, or of from 2 to 10 such lines, 

 joined at the ends to form acute angles. Under magnification the 

 lines show distinct cross figurations. (PI. II, B) These marks on 

 the leaves usually may serve as the best means of determining the 

 presence of the curculio in any locality, since in badly infested dis- 

 tricts, especially in the autumn, the foliage is thickly specked with 

 them. The health of the vine is not impaired to any appreciable 

 extent by even great numbers of the marks, but this feeding habit 

 is otherwise important as furnishing an easy means of control. 



Careful measurement of 50 feeding marks showed that the average 

 area covered by each was 3 square millimeters. In order that some 

 idea of the individual feeding capacity of the beetles might be gained, 

 24 pairs were confined in jars and supplied daily with fresh grape 

 leaves and fruit. Every morning counts were made of the marks on 

 the leaves eaten by each pair. This w T as continued from July 9 to 

 September 30, a period of 84 days. On the last-named date feed- 

 ing was discontinued, all the beetles having died or entered hiberna- 

 tion. Table I shows the results of these counts. 



Table I. — Number of feeding marks made in grape leaves by 24 pairs of the grape curculio 

 during the period from July 9 to Sept. 30, 1917. 



Pair No. 



Number of 

 feeding 

 marks. 



Pair No. 



Number of 

 feeding 

 m-.irks. 



1 



1,128 

 1,404 



431 

 1,076 

 1,084 

 1,202 



701 

 1,233 

 1,311 



874 

 1,164 

 1,413 



13 



1,333 

 1,225 

 1,180 

 1,127 

 1,139 



688 

 1,180 

 1,222 

 1,297 

 1,301 

 1,549 



972 



2 



14 



3 



15 



4 



16 



5... 



17 



6 



18 



7 



8 



19 



20 



9 



21 



22 



10... 



U 



23 



12 



24 



Total 





27, 227 



