242 REPORT OF THE COMMISSIONER OP AGRICULTURE. 



iione by. While a number of instances have been reported, we have 

 been unable to get any information of a reliable character that would 

 tend to alter the conclusions to which we came in 1868, and which were 

 published in the Cicada bulletin. These were, substantially, that while 

 in the latter part of the season a severe sting may be inflicted by some 

 hornet (genus Stizus) flying against a person while carrying a Cicada 

 intended for burial in the ground as food for its young, yet it is more 

 than probable that the sting results from the exceptional puuctine by 

 the beak or haustellum of the Cicada, the nature of the wound that is 

 inflicted depending very largely on the condition of the system of the 

 person punctured. All our experiments the past season seem to con- 

 firm the imi)robability that the ovipositor is used or can be used on 

 human flesh for this purpose. 



OVIPOSITION. 



While there is a general impression among those who have not closely 

 observed the facts that the female Cicada^ purposely severs or partly 

 severs the twig upon which she has oviposited in order to cause it to 

 break and die, no such opinion is held by any one who has carefully 

 studied the facts. The nature of the perforation and the manner in 

 which the eggs are inserted are well illustrated in Plate Y, Fig. 1. So 

 far from purposely severing or causing the severance of the egg-charged 

 twigs, it is a fact that the eggs, in almost every instance, in twigs which 

 have broken early or have fallen to the ground, shrivel up and fail to 

 hatch. The breaking is merely accidental and confined to the small ter- 

 minal twigs, and results from too close sawing or rasping, which weak- 

 ens the wood so that it breaks with a strong wind. In tough wood the 

 twig may be partly broken, and is then generally worn and twisted by 

 the movements caused by the wind, as shown in our figure (PI. V, Fig. 2). 

 The i)roportion of severed or broken twigs or heavily cluirged twigs upon 

 which the leaves prematurely die and dry, though it may be sulficient 

 to give a withered appearance to the whole exterior portion of the tree, 

 is but small compared with the thicker and stouter twigs which are 

 punctured. In other words, 90 per cent, of the eggs, and i)robably 99 

 per cent, of those which hatch, are laid in twigs which never break off. 



We have observed some interesting instances of retarded develop- 

 ment in the" eggs of this Cicada when placed in the twigs of trees which 

 exude some gummy substance, so as to hermetically close up the open- 

 ing of the puncture'and exclude the air. We have been surprised to 

 find that such eggs, which would have normally hatched during the 

 latter part of July, or about six weeks after being deposited, have re- 

 mained sound, but unhatched, up to December, and long after the trees 

 had shed their foliage. 



INJURY WHICH CICADAS CAUSE TO FEUIT TREES — REMEDIES AND 

 PREVENTIVE MEASURES. 



This Cicada in its underground life has been charged with injuring 

 and killing fruit trees. From what we have already stated as to this 

 underground life — its long duration and its slow development — as well 

 as for other reasons, such injury must necessarily be very trifling; and 

 this fact is borne out by some observations which we made the past 

 summer. Even where the insects have been so thick in orchards that 

 the ground was absolutely honey-combed by their perforations, an in- 

 spection of the roots of these trees showed no injury, and in fact scarcely 



