346 The Ohio Naturalist. [Vol. V, No. 7, 



LIFE HISTORY NOTES ON APION NIGRUM. 



E. C. COTTOX. 



The genus Apion, family Curciilionidae, contains several 

 serious pests among which are two or three that do considerable 

 damage to the clover plant. Two members of the genus A. 

 nigrum and ^4. rostruin belong to the fauna of the black locust 

 {Rohinia pseudacacia) . Our knowledge of the habits and life 

 history of these two species is incomplete. It has long been 

 known that the adults of ^4. nigrum feed upon the black locust, 

 eating holes in the leaves and it has been supposed that the lar- 

 vae, as the larvae of nearly related species, "develop within the 

 seeds of this tree" (Insect Life, 5:338). However, the seeds of 

 the black locust are but little larger than the adult curculio so 

 that this could hardly be true, and some observations made 

 during the past summer disprove this supposition. 



While engaged as Assistant Nursery and Orchard Inspector 

 the writer visited Marietta on May 22, 1904, and found many 

 adults of A. nigrum working upon the unopened flower buds of 

 the black locust trees west of that town. On closer observation 

 it was noted that the females were puncturing the buds and 

 ovipositing in the holes thus made. On a second visit to this 

 locality, on May 26, the insects were as numerous as before and 

 it was noted that many of the buds had ceased to develop and 

 were falling to the ground where they remained fresh for some 

 time. Many of the fallen buds had the pedicle still attached, 

 but a larger part did not. An examination showed that nearly 

 all of the prematureh" falling buds had been punctured in one or 

 more places, and upon opening them, all stages of the insect were 

 found, i. e., eggs, larvae, pupae and adults. Usually only one 

 stage of the insect was found in a single bud and normally but 

 one develops in a given bud yet there may be two or more. 

 From some of these buds the adults had emerged by eating a 

 round hole, generally through the base of the bud but some ate 

 their way out at about two-thirds of the distance to the tip. 



One raceme upon which twelve adults were observed feeding 

 and ovipositing, was found to contain thirty buds, twenty-five 

 of which had been punctured in sixty-three separate places. 

 The highest ntimber of punctures in any one bud was seven. 

 From thirty of these wounds a viscid, gummy substance was 

 exuding. About fifty of these buds were collected from the 

 ground and placed in a glass jar, on May 26th, and on June 5th, 

 twenty adult curculios, one pupa and four larvae were taken 

 out, and on June 11th, seven more adults were removed. 



