71 



from the head and the adult moth slowly drags itself forth. The emergence occupies 

 in the neighborhood of five minutes, when the freed moth climbs upon some nearby 

 object to expand and dry its wings in readiness for flight, which can be accomplished 

 in a matter of fifteei> minutes following emergence. 



Plate I, figure 1, is a record of continuous observations from 1920 to 1923, and 

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

 at Amherst, and the average period of greatest abundance. The motlis -aw i)r(^sent 

 in numbers from the last of June until the first week in August. They dait from 

 plant to plant in the heat of the day, and their rapidly vibrating ^vings and brilliant 

 coloration cause them to be easily mistaken for wasps. They are fairly strong 

 flyers, and the writer has known them to locate scjuash fields removed one-half 

 mile from where cucurbits were growni 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 bj-^ 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 diflferent parts of the plant. The data are presented in Table I. 



Table I. — Location of Squash Vine Borer Eggs. 



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. 



