EXPERIMENT STATION BULLETINS. 273 



pelled to, come to the upper world at the same time. The life of the 

 mature insect lasts but a short time, a week or so. The eggs are laid, 

 aud all is over. By the first part of July the insects are gone in Michi- 

 gan. The eggs are deposited in the branches of trees, in holes bored by 

 the ovipositor of the female. See fig. 22. Eight here all the damage, if any, 

 is done. The numerous holes in the twigs kill a few of them, but at most, 

 it can only amount to a severe pruning from which the tree usually re- 

 covers quickly. The larvae from the eggs fall to the ground and burrow 

 out of sight. Now commences the long underground existence, during 

 which thej^ feed on the roots of trees. The places frequented are usually 

 woodland or land that was wooded originally. Owing to the large areas 

 cleared in recent years, the number of cicadas is steadily decreasing. 



Curiously enough, the entire area in the United States inhabited by 

 these insects, may be divided into two regions, a northern and a southern, 

 which regions slightly overlap. The southern region is inhabited by a 

 race which occupies thirteen years in development, while the northern 

 region supports a race requiring seventeen years. 



The entire number of seventeen- vear cicadas is divided into twentv- 

 two broods, each of Avhich emerges at a well-known time and occupies a 

 well-defined area. Michigan is visited by three of these broods and pos- 

 sibly by a fourth. The broods for 1902, 190.5 and 1911 visit Michigan, 

 and possibly the one for 1898. 



The last brood, the one for 1902, occurred at Battle Creek, Kalamazoo, 

 Ann Arbor, Ypsilanti, Adamsville, Bitely, Flint, Birmingham, and ques- 

 tionably at Moorestown. Several of these records were obtained for me 

 through the kindness of Director C. F. Schneider of the weather bureau. 



The song of the cicada is very characteristic. It is produced by a pair 

 of small organs on the first abdominal segments. The tone is shrill and 

 not unlike the sound of a distant mower ; when many are singing together, 

 the sound may become monotonous. The bite of the cicada seems to be 

 rarely experienced. Many newspaper accounts would lead one to regard 

 the harmless insect with fear. The writer observed a single case. While 

 handling and examining a number, the lady in question received a sharp 

 thrust from the beak of one. The pain was no greater than would have 

 l">een inflicted with a needle, and this quickly passed away without return- 

 ing. 



A fungus disease Massospora cicadina, was observed to be common 

 at Ann Arbor and vicinity. The fungus absorbs the tissues of the living 

 insect without seeming seriouslv to interfere with its comfort. Manv 

 adults were seen walking about without the apical part of the abdomen 

 and occasionally one with the whole abdomen gone. 



No damage was reported during the last outbreak in Michigan. There 

 is little to fear, unless a young orchard has just been set out on land 

 previously wooded, and where the insect has been seen in the past. 



THE AXGOUMOIS GRAIN MOTH. 



{^itotroga cerealella*) 



Nearly two hundred years ago an interesting insect was, in some way, 

 introduced from France into North Carolina. Here it became acclimated 



*Kinclly determined for me by Miss Mary E. Murtfeldt and by Mr.Busck of the Department of Agri- 

 c nture. 



35 



