288 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



PREDACEOUS. 



Spiders {Araneida). — That the numerous spiders, always to be found 

 about cotton fields, do a considerable amount of good in capturing the 

 cotton-worms and the cotton-moths cannot be doubted. The jum]>ing 

 spiders (Attides) destroy many young larvae and occasionally are able to 

 capture a moth. Plate IX, fig. 5 represents a species which was observed 

 by Mr. Trelease to prey ujjon the cotton- worm. 



The large nesting spiders {Ejyeirides), of which the commonest species 

 through the Southern cotton fields is Argiope riparia {JEpeira riparia of 

 older authors), catch the moth in their webs. 



A common and doubtless a beneficial species, which I observed upon 

 the cotton plant in Alabama, is a large pale-gTcen spider, with long spiny 

 legs {Oxyopes viridans). (See Plate IX, fig. 6.) 



Clubiona pollens was found nesting in cotton quite abundantly. They 

 fold the cotton leaves in much the same manner as do the cotton-worms, 

 forming thereby a sort of basket, in which they deposit their eggs. 

 They may at once be distinguished from the Aletia web by the white- 

 ness of the silk of the former. 



Among the smaller species which have been noticed upon the plant 

 among the young worms may be mentioned Attus fasciatus, Theridium 

 globosum, Theridium funehre^ Epeira stellataj Sinyphia communis^ Tetra- 

 gnata extensa, Meiha sp., and Xysticus sp. * 



Of the true insects that prey upon the eggs, larvae, or adult of Aletia 

 argillacea, some 35 species have been observed by the correspondents 

 and observers of the department. Of these we shall speak in their 

 regular scientific order, beginning with those belonging to the Neue- 

 OPTERA, the lowest order of insects. 



Aphis lions {Neur., gen. Ckrysopa). The aphis lions are the larvae of 

 the "golden-eyed lace- wing flies" — insects with slender bodies and ex- 

 tremely delicate, gauze-like wings. Their color is usually green and 

 their eyes golden (represented in all stages in Plate IX, figs. 7 and 8.) 

 Upon being disturbed, they emit a disagreeable, fetid odor. Their eggs 

 are white and are supported by long foot-stalks, as shown in the figure, 

 usually ui^on plants infested with plant-lice. The larvae are active and 

 extremely voracious. There are two or more broods in the course of 

 the summer, and the last brood winters in the chrysalis state, protected 

 by a compact, round, whitish cocoon. 



These aphis lions are abundant upon the cotton-plant throughout the 

 summer, and in the early part of the season do the planters much good 

 by destroying the cotton-aphides in large numbers. Later in the sea- 

 son they devour the eggs and newly-hatched larvae of the cotton-moth. 



Mosquito-hawks, Dragon-Flies, or Devil's Darning-needles 

 {Nenr., Fam. Lihellulidae). — These insects, in the adult stage, are so well 

 known as not to warrant description. The eggs are laid in the water, 

 either indiscriminately dropped or deposited around the stem of some 

 aquatic plant. The larvae are predaceous, living upon other aquatic 

 insects. The habits of the perfect insects are also predaceous. (We 

 figure (Plate X, fig. 1) one of the most common species, Libelula trimac- 

 ulata.) They catch and eat numbers of insects upon the wing. 



In the next order, Orthoptera, we find but one insect which preys 

 upon Aletia argillacea; altliough in parts of Texas, according to ]\Ir. 

 Sclawarz, the planters insist that the grasshoppers eat the cotton- worm! 



The Rear-horse, Camel-cricket, or Devil's Eiding-horse {Man- 



* The determinations of tlie spiders mentioned in this report were made by Mr. 

 George Marx, of fhis department. 



