236 REPOKT OP THE COMMISSIONER OF AGRICULTURE. 



" I took pains to follow the larval development as far as possible from 

 year to year, of the tredecim broofl which appeared in 1888, my obser- 

 vations having been made in Saint Louis County. Eepeated efforts to 

 rear the young larvte in coufinement proved unsuccessful, and it was 

 necessary to resort to careful and repeated digging in order to watch 

 the growth from year to year. One of my employes, at Cadet, Mo., has 

 also been instructed to carefully pursue the same subject, and I have 

 repeated the digging since residing in Washington. These observations 

 liuve in all cases been made in special localities where the date of enter- 

 ing the ground was well known and observed. I have thus been able 

 to follow the larvse for the first six years with great care, and for sub- 

 sequent years with less care and continuity. As we might expect from 

 the chronological history of the species, the development of the larva is 

 extremely slow, and at six years old it has hardly attained one-fourth its 

 full size. Another interesting result is. that notwithstanding this slow 

 develojDment, molting takes place quite frequently, *. c, the number of 

 larval stages is more than one per annum, and probably twenty-five or 

 thirty in all ; whereas in Homoptera generally — the suborder to which 

 the Cicada belongs — it ranges from two to four. In any hypogean in- 

 sect which continually uses its claws in burrowing, the need of shedding 

 and renewing those organs is apparent and may afford the chief expla- 

 nation of this repeated exuviation, though the slow development is a 

 factor, since my own experience has shown in the larva? of other Orders, 

 that in proportion as development is slow, exuviation is frequent. The 

 changes with each molt are, in our young Cicada, most noticeable in the 

 antenufe and in the front legs and their armature, for the general form 

 undergoes but little change, the body very gradually shortening and 

 thickening, and the color darkening with age. 



THE FOOD OF THE LARVA. 



"A good deal of difference of opinion has been expressed by differ- 

 ent writers as to the food of the Cicada larva, and this is not to be 

 wondered at, frou) tbe fact that there is great difSculty in observing it 

 feed. Dr. G. B. Smith insisted that it obtained its nourishment from 

 the moisture of the earth through capillary hairs at the tip of the pro- 

 boscis, while others have seen it with its beak inserted in the roots of 

 trees and pumping the sap therefrom. My own observations indicate 

 that both methods of obtaining nourishment may obtain. The former 

 method I have never witnessed, but it is insisted on by Dr. Smith from 

 his own observations, and receives support from the well-known fact 

 that this Cicada will issue from ground that has been cleared of timber 

 and cultivated for nearly seventeen years, and that other species are 

 known to issue from the praii-ies. The truth of the matter seems to be 

 tliat the Cicada can and does go for long periods without nourishment, 

 v.here such fasting is necessitated, and that in the earlier years of its 

 development, more particularly, it feeds on the rootlets or railiceis, not 

 alone of trees, but of herbaceous plants. In my own observations V 

 have rarely found it more than 2 feet below the surface during the Ih'st 

 six or seven years of its life, and almost invariably in an oval cell, :nul 

 more often away from roots than near them. Yet I have also ibuud it 

 with beak inserted, and it will often hang fast by the beak after being 

 unearthed. That the larva is capable of going to great depths seems to 

 be well attested by observers, and I have recently received a cummuui 

 cation where the writer says he has found it 20 feet below the surface. 



" It is difficult to say how many of such reports are based on the 



