3 



and indicates an average seasonal occurrence of the different life stages of the 

 insect at Amherst, and the average period of greatest abundance. The moths 

 are present in numbers from the last of June until the first week in August. 

 They dart from plant to plant in the heat of the day, and their rapidly 

 vibrating Avings and brilliant coloration cause them to be easily mistaken for 

 wasps. They are fairly strong flyers, and the writer has known them to locate 

 squash fields removed one-half mile from where cucurbits were grown the 

 previous year. 



The female moths lay their eggs singly, going from hill to hill, depositing one 

 to several eggs on each plant. The eggs are attached by the flattened base, and 

 are held in place by a cement-like secretion. Individual moths seem to have 

 different tastes regarding the location selected for the eggs. In following moths 

 from hill to hill, some are observed to seek the junction of the stem and the 

 ground, some oviposit upon the leaf-stalks, and some even tuck the eggs down 

 between the squash stem and the surrounding soil. Other moths lay their 

 eggs indiscriminately upon main stem, leaves, leaf-stalks, and even upon tendrils 

 and blossoms. The favorite location, however, appears to be the main stem near 

 the base. Several counts have been made to determine the percentage of the 

 total number of eggs laid on the different parts of the plant. The data are 

 presented in Table I. 



Table I. — Location of Squash Vine Borer Eggs. 



On On Leaf- On 



Stem. stalks. Leaves. Total. 



Lexington, 1922 . 377 299 10 686 



Amherst, 1922 . 168 48 216 



Littleton, 1923 .48 5 7 60 



Amherst, 1923 . 426 36 23 485 



Total . . 1,019 388 40 1,447 



Per cent of total . 70.4 26.8 2.8 



Individual moths may lay as many as one hundred fifty to two hundred eggs. 

 Theoretically, therefore, ten moths only, flying from plant to plant and each 

 laying a total of one hundred fifty eggs, are necessary to cause a one hundred 

 per cent infestation of fifteen hundred plants, which is perhaps the average 

 number of plants per acre. 



Eggs are to be found from late June or early July until mid- August, and even 

 later in some seasons. The period spent in the egg stage has been placed by 

 various investigators at from six to fifteen days. Breeding records at Amherst 

 show a variation of from nine to thirteen days, but they are not extensive 

 and may not represent the extremes for this climate. 



Table II. — Length of Egg Stage, Amherst. 



Number Number 



OF Egos. Eggs laid. Eggs hatched. of Days. 



10 . . Julv 29, 1920 Aug. 11, 1920 13 



4 . . Aug. 4, 1923 Aug. 13, 1923 9 



1 . . Aug. 5, 1923 Aug. 14, 1923 9 



The records are those obtained from eggs laid by confined moths. Eggs 

 collected in the field showed a high percentage of parasitism, which is dis- 

 cussed in another section of this paper, and were quite unsatisfactory for rearing. 



When emerging from the egg, the young larva chews a ragged hole in one end 

 and crawls forth upon the surface of the squash plant. Its subsequent action 

 shows considerable variation in habit. In many cases it burrows directly into 

 the host tissue. In other instances neAvly-hatehed larvae have been seen to 

 crawl to distances of eight to ten inches from the egg-shell, feeding here and 

 there on the leaf or stalk before finally tunneling out of sight. Those Avhich 

 invade the leaf-stalks and main leaf veins gradually work their way toward the 

 main stem. Since the average squash plant has not put forth runners when the 

 majority of the eggs have been laid, the result of this Movement is a concen- 

 tration of injury in the main stem near the base. 



The burroAV made by the squash vine borer larva is a tAvisting one, and is 



