April, '17] HAYES: LIGYRUS GIBBOSUS 257 



The full-grown larva (PI. 12, fig. 3) is about 31 mm. long and 9 mm. in 

 maximum width. The head is brown in color and rather roughly re- 

 ticulated. The whole body color is of a bluish tinge as are the grubs 

 in the genus Cyclocephala. The spiracles are brown and somewhat 

 prominent. The last abdominal segment bears ventrad a patch of 

 short, straight hairs arranged triangularly. The double row of spines, 

 found in this region in Phyllophaga and other genera, is absent. Dor- 

 sad, the last segment is devoid of hairs, but a few are present along the 

 sides. The anal slit is transverse. Spines are present on the upper 

 surface of the thorax and abdomen, but they do not seem to be as con- 

 spicuous as in Phyllophaga. As is the case with other grubs, three 

 pairs of legs are found. The larva may crawl either on its side or on 

 its feet and, when disturbed, lies coiled on its side. 



In Kansas, the grubs have been found feeding on the roots of corn, 

 oats, and wheat. They also thrive in soil that is rich in decaying 

 organic matter, such as pasture land and freshly manured fields. In 

 rearing cages, during the early part of the larval stage the grubs were 

 successfully reared in soil mixed with manure. When about half 

 growm, the larvse were transferred to soil containing germinating wheat 

 where they thrived on the roots, and frequently whole kernels of wheat 

 were eaten before the seed had an opportunity to sprout. 



In soil cages, freshly hatched larvse were frequently seen eating each 

 other. This habit probably accounts for a considerable amount of the 

 exceedingly high mortality in rearing cages. During the past summer, 

 out of 555 larvse hatched from eggs, only 38 were successfully reared 

 through to the pupal stage. The greatest death-rate occurred in pot 

 cages containing fairly large numbers of grubs. The mortality is also 

 high in cages where the larvse are kept isolated. 



The Prepupal Stage. — The grub, when full grown, sheds the 

 meconial mass in the digestive tract and assumes a quiescent or pre- 

 pupal stage. TJie body becomes smaller, being about 25 mm. long and 

 7 mm. wide across the thorax. The bluish tinge is lost and the grub 

 becomes white in appearance except for the last three or four abdominal 

 segments which remain darker and are much wrinkled, giving this end 

 of the body a glistening appearance. 



Previous to the transformation to the prepupal condition, the larva 

 enlarges its burrow in the soil by packing the surrounding earth. Here 

 it changes to the prepupa and later to the pupa. The coiled prepupa 

 lies on its side and wa-iggles actively when disturbed. 



The combined length of the larval and prepupal stages was found to 

 average 59.2 days for 36 specimens with a maximum of 80 days and a 

 minimum of 43 days. The following table shows the exact length of 

 each stage : 



