THE AMERICAN ENTOMOLOGIST. 



141 



plaint, or some other one of those nuineroiis 

 .ailmeuts which are especially prevalent in the 

 summer season. Anil it will be only in the 

 hundredth case, that attention will be called to 

 their existence among the fieces; and even then 

 probably not a hundredth part of such cases 

 will be recorded in printed books, because most 

 persons will be apt to confound together those 

 larvae which habitually live in decaying vegeta- 

 ble matter, and the ordinary Intestinal Worms 

 (Entoioa) , the native home of which is in the 

 body of some animal or other. Taking every- 

 thing into consideration, we doubt whether, out 

 of ten thousand cases, where the larva- ,of Two- 

 winged Flics have existed in considerable num- 

 bers in the human intestines, more than one 

 single case has been recorded in print for the 

 edification of the world by competent entomo- 

 logical authority. And if this be a correct esti- 

 mate, we may see at once how fearfully common 

 such larviv must be in the bowels of that most 

 patient of all military heroes — General Public. 

 Moral.— Avoid eating decayed fruit, espe- 

 cially if you are in poor health, and from fruit 

 which is only partially decayed pare away care- 

 fully the unsound parts before you introduce the 

 sounder portions into your stomach. Every 

 entomologist knows what a pleasing pursuit it 

 is to breed insects through all their stages in 

 appropriate vessels ; but to breed them in one's 

 (iwn body is rather too much of a good thing. 



PLVNT-LICE AND THEIR ENEMIES. 



Early in September I found ray Chrysanthe- 

 mums badly infested with black plant-lice — 

 the species most often attacking the Composite 

 family of plants — and a few moments' observa- 

 tion convinced me that this would be a grand 

 opportunity to capture and study the various 

 insects that visited them; and I concluded to 

 sacrifice the plants, if need be, to this excellent 

 opportunity of studying insects so close at the 

 door. So, every pleasant day found me at my 

 post, equipped with a low foot-stool for a scat, 

 a good lens, and several glass tumblers in which 

 to make my captures. 



In a few days I had taken over thirty distinct 

 species of Ichneumons, among which were rare 

 ones that would delight the heart of an Ento- 

 mologist to see. Some of these Ichneumons 

 were attracted merely by the sweets given out 

 by the plant-lice, which they eject through two 

 honey-tubes near the extremity of the body. 

 Sometimes there will be quite a little shower 

 of this honey scattered upon the leaves below, 

 as I have frequently felt it falling upon my hand. 



Various insects are attracted by this honey, 

 which they lick off from the stems and leaves; 

 while others, such as the Syrphus-flies, come 

 for the purpose of depositing their eggs along 

 the infested stems, which eggs are soon hatched 

 into larvas that feed upon the plant-lice; and 

 still others come for the purpose of depositing 

 their eggs in these Syrphus-fly larva?. 



There were several species of these gaily- 

 dressed Syrphns- flies very busy about the 

 plants; and I soon found that they were not 

 attracted by the sweets like some of the other 

 two-winged flies, neither were they preying 

 upon their neighbors, like some other tribes 

 that visited here, but they were depositing their 

 eggs along the stems infested with the plant- 

 lice. And I resolved to. experiment with these 

 different species. So, cutting several stems of 

 Chrysanthemums, that were nearly covered 

 with the black lice, I placed them in a small 

 glass jar of water for keeping fresh, and cov- 

 ered the whole with a large oval glass. I then 

 caught several of the flies and introduced them 

 under the glass, where they blindly knocked 

 their heads against the glass in the hopeless en- 

 deavor to escape. But finding all such attempts 

 fruitless, they were at length resigned to their 

 fate, and quietly settled down and began to 

 examine the plants, and deposit their eggs 

 among the plant-lice. The eggs hatched in a 

 day or two into very minute whilish-looking, 

 footless grubs ; and here in the midst of their 

 food, all the grubs had to do was to seize each 

 a plaut-lousc, larger than itself, and, sucking 

 out its juices, drop its lifeless body. 



These Syrplius larvre grew rapidly, and soon 

 changed to a dark color, although I could not 

 see that they changed their skins. Dark lines 

 ran along the back, and the body was variously 

 mottled with sober brown, very unlike their 

 brilliantly attired parents. 



When fully grown some of the larger species 

 were an inch or more in length, and at this 

 stage of their lives, very quickly would they 

 clear a stem of plant-lice. Eating was the grand 

 business of their lives; almost too lazy to move 

 along after their food, they would stretch them- 

 selves to an incredible length in trying to reach 

 a plant-louse, rather than take a step in advance. 

 Alter one had seized its victim, it elevated its 

 head perpendicularly, holding the plant-louse 

 up in the air until its juices were extracted, and 

 then with a sudden jerk throwing its lifeless 

 body down. 



When they were ready to assume the pupa 

 form they ceased eating, and became quite 

 uneasy, and I found they could crawl quite 



