﻿STEAWBEKBY KOOTWORM ON GEEENHOUSE ROSES 



13 



Sixty adults given fresh leaves twice daily ate 372 of the charac- 

 teristic "shot-hole" punctures (fig. 1) the first day, 386 the second 

 day, and 325 the third day, averaging 6.2, 6.4, and 5.4 feeding punc- 

 tures per adult on the respective days, or an average over the whole 

 period of 6 such areas for each beetle per day. It was observed 

 to require about six minutes for a beetle to eat one hole in a leaf. 



Further experiments, as indicated in Table 4, gave an average of 

 between 4 and 5 feeding punctures per day for each individual. 



Table 4. — Amount of feeding ty strawberry rootworm beetles during 



September, 1921 



Period 

 (first and last dates, inclusive) 



Number of— 



Feeding punctures- 



Days 



Adults 



Total 



Average 











number 



Per day 



Per adult 

 per day 



3 



47 



645 



215 



4.57 



4 



46 



1,103 



276 



6.00 



4 



45 



947 



237 



6.27 



4 



43 



704 



176 



4.09 



3 



43 



528 



176 



4.09 



5 



43 



463 



93 



2.16 



5 



43 



446 



89 



2.07 



Remarks 



Aug. 31 to Sept. 2.. 

 Sept. 3 to Sept. 6... 

 Sept. 7 to Sept. 10- 

 Sept. 11 to Sept. 14 

 Sept. 15 to Sept. 17 

 Sept. 18 to Sept. 22 

 Sept. 23 to Sept. 27, 



1 dead. 



Do. 



2 dead. 



PEOTECTIVE HABITS 



As is characteristic of certain other insects, this beetle at the least 

 disturbance folds its legs and antennae under its body, rolls from 

 the leaf, and remains motionless on the ground for several minutes. 

 This so-called "possum" or death-feigning habit is also protective 

 and is more common than the " squirrel " habit, by which they 

 escape being seen. If approached during the day, any beetles visible 

 on the plants immediately conceal themselves behind leaves, stems, 

 stakes, or elsewhere. • When one walks through a heavily infested 

 house at night he can hear the beetles dropping from the bushes 

 about 10 feet ahead, and when the beetles are present in large 

 numbers the sound is similar to the patter of a gentle rain. The 

 coloration of the beetles blends with that of the earth or mulch, and 

 it is difficult to locate them on the soil unless they move. 



The beetles do not necessarily reach the ground when they drop 

 from the plants, for they are apt to fly at any time during their fall. 

 In fact, when within a foot of the soil they have been observed to 

 spread their wings and fly to near-by leaves. The range of con- 

 tinuous flight appears to be limited, as 30 feet was the maximum 

 distance observed. In one house, where the plant tops had been cut 

 back and removed during the day, many beetles were seen on the 

 walls and roof, where they were apparently trying to escape from 

 the house by making short flights of from 5 to 10 feet at a maximum 

 altitude of 10 feet. 



FERTILITY AND PARTHENOGENESIS 



Mating was not observed and males have never been seen among 

 the numbers of individuals collected under glass. Peterson {23, p. 



