June, '22 weigel & doucette: strawberry root worm on roses 205 



up to 15, averaging about four per mass, and records show that a female 

 may lay as many as 216 eggs during its life. The period of incubation 

 varies from a minimum of seven (7) days to a maximum of twenty- 

 seven (27) days. When first laid the eggs are white in color, later 

 becoming yellow, and each egg mass is surrounded almost invariably 

 by a heavy cement-like secretion. The egg is about 1 mm. in length 

 and elongate oval in shape. While egg-laying is continuous throughout 

 the first eight months of the year, there are two periods when egg de- 

 position is particularly marked, viz., in March and April and in June 

 and July. 



The Larva : The newly hatched larvae, which are very active, enter 

 the soil immediately where the development of both larvae and pupae 

 takes place. The full grown larvae are about 5 mm. long; white in 

 color ; except the head and tips of claws which are brownish ; resembling 

 white grub larvae except for size. It was found that the larvae require 

 from sixty to seventy-four days to complete growth. In this stage 

 considerable injury is done to the roots of the plants. 



The Pupa : When ready to pupate the larva hollows out a cell in the 

 soil and there transforms to the pupa which emerges as an adult after 

 eight to thirteen days. 



As high as twenty-three specimens of the soil forms, i. e., larvae and 

 pupae have been found around the roots of a single rose plant at depths 

 varying down to four inches. The greater part of the larvae and pupae 

 are usually located directly in the ball of roots. 



The Adult: The average longevity of the adult has not yet been 

 definitely determined owing to the long period of egg-laying and sub- 

 sequent overlapping of broods. Adults collected in the greenhouses 

 and kept under constant observation have lived a maximum of 141 

 and 156 days. Adults reared from pupae in early June lived (1) Dec. 

 3 — 160 days. — (2) Dec. 23 — 180 days and in that period deposited about 

 40 eggs. Further experiments are now in progress to determine the 

 remaining features of the adult stage. 



Seasonal History: From the observations thus far taken it appears 

 that the adults which emerge in September and October spend the win- 

 ter hiding in mulch or soil, occasionally coming out to feed on clear 

 sunny days. After early February they are found more frequently 

 on the plant. Egg laying commences the latter part of February 

 and continues through March and April with some egg-laying at all 

 times throughout the spring months. Adults are not very numerous 

 during the latter part of April and in May, but appear in large numbers 

 in June and July. During the latter two months a considerable num- 



