330 



THE AGRICULTURAL NEWS. 



October 20, 1906. 



INSECT NOTES. 



A New Sugar-cane Pest. 



During the past few months sugar-canes in 

 Trinidad have been attacked by a small insect of 

 the group known as spittle insects or frog-hoppers. 



The name spittle insect is, given on account of the 

 peculiarity of the inmiature insect in covering itself in 

 a mass of white troth which is voided from the tip of the 

 abdomen, and which forms a complete hiding-place or covering 

 for the insect within. The name frog-hoppers was proltabl^' 

 derived from the name of frog-spittle, formerly given to 

 the frothy mass, and from the leaping habit of the adult. 



The frog-hoppers belong to the family Cercopidae, of the 

 order Hemiptera, and are therefore related to the principal 

 insect pests with sucking mouth-parts, such as scale insects, 

 plant lice, plant bugs, cotton stainers, etc. 



Specimens of infested cane stumps and of the adult 

 insect have been forwarded from Trinidad to the Head Office 

 of the Imperial Department of Agriculture, and the following 

 account is based on e.xamination of these specimens. 



The adult insect is about ^^ inch in length, and about 

 half as wide. The head and thorax are dark greenish, the 

 wing-covers light-brown with two narrow whitish bands 

 running across them. The head is stout and broad, the eyes 

 prominent, and there are two small simple eyes on the upper 

 surface of the head between the large compound eyes. The 

 antennae are .short and hair-like, except the base, which is 

 inueh thickened. The legs are dark-brown and slender ; the 

 wing-covers are somewhat thickened, while the under wings 

 are pale, tinged with smoky-brown, and with violaceous 

 reflections. The immature specimens, so far examined, are all 

 in the last larval stage of development. The bodies are 

 whitish, tinged with pink or red, the head and thorax being 

 darker. The developing wings are seen as dark, elongated 

 pads lying on the basal part of the abdomen. 



The adults have not been observed in the act of feeding. 

 The immature insects seem always to place themselves on 

 young tender roots, and it is probable that the)' are unable 

 to penetrate the hard rind of the cane with their beaks. 

 They have been found feeding at a distance of 4 inches below 

 the surface of the soil. 



Jlr. .J. H. Hart, in a letter to the Imperial Commissioner 

 of Agriculture, states that this insect apiieared a few years 

 ago in Trinidad, during such a season of constant wet 

 weather as the present has been, and the fact that it has 

 remained comparatively unknown since that time would 

 indicate that it becomes a pest only in seasons unfavourable 

 to the cane. 



The insect will probably prove to be a species of 

 Tomaspis, perhaps T. bichicta. 



It may be added that the specimens of cane stumps 

 forwarded for examination were attacked by the root fungus 

 {lilarasmitis), and several of the canes had been comjiletely 

 tunelled out by some boring insect, so that it is quite likely 

 that the unfavourable condition of the cane fields from which 

 the specimens were taken may be largely due to other causes 

 than the frog-hoppers. 



Proliferation in Cotton Plants. 



The Bureau of Entomology of the U. S. Depart- 

 ment of Agriculture has recently issued a bulletin 

 (No. 59) entitled ' Proliferation as a Factor in the 

 Natural Control of the Mexican Cotton Boll Weevil.' 



It is .shown tiiat the buds and bolls of cotton have the 

 power of producing a growth of loose tissue, when wounded 

 by insects or ntherwise, which seenis to be an effort on the 

 part of the plant to offset or check the injury. The amount 

 of loose tissue |)roduced in this proliferation is in many cases 

 sufficient to fill the cavity or wound, and when the larva or 

 pupa of the boll weeviMs in such a cavity, it is crushed by the 

 pressure of the growing plant cells. 



Proliferation has been found to occur in upwards of 50 

 per cent, of the buds and bolls injured by the boll weevil 

 which were examined, and the different stages of tiie weevil 

 were killed by the pressure of the proliferation in 135 per 

 cent, of the buds and in G'3 per cent, of the bolls. 



While this power of adaptability may not by itself 

 become a powerful factor in the control of the boll weevil, it 

 may be turned to good account when taken into consideration 

 with other characters in selecting weevil-resistant cotton, and 

 is, at least, interesting as .showing the power of adaptation on 

 the part of the [jlant. Probably also the insects will develop 

 characters to offset more or less the proliferation of the 

 cotton, which, if left entirely to natural courses, would tend 

 to establish an immunity to its effect. 



West Indian Digger Wasps. 



In a recent paper on the digger wasps of North 

 America and the We,st Indies {Proceedings of the U.S. 

 National Miiseum,\[o\. XXXI, pp. 291-423), Dr. H. T. 

 Fernald mentions a peculiar case in the identity of 

 two species of these wasps. The last paragraph 

 under the heading of C'Idorion spiniger is as follows : — 



I have studied examples of Chlorion fj^iniger from 

 Florida, Louisiana, Mississippi, Texas, Santo Domingo, 

 Barbados, Dominica, and Trinidad. Kohl records it from 

 Me.xico and Brazil. In quite a large lot of specimens of 

 Chlorion from the above-named West India Islands all the 

 males were spiniger and all th? females dubitatwn, which is 

 rather .suggestive of a relation between these species, and 

 which is considered under duhitatutn. 



The last paragraph of the consideration of CIdorion 

 dahitatam is as follows: — 



Accepting dulitaf urn as a good species, we find that all 

 the specimens are females. A closely related species is 

 spiniger, of which only males are known, found in the same 

 territory, and in quite a collection of the.se insects from the 

 West Indies which I have studied, every female WAsdu/iitatuiii 

 and every male was spiniger. Taking these facts into 

 consideration, I am of the opinion that these species will 

 ultimately prove to be identical. 



Green Page Moth. At the present time a moth 

 is being found in Barbados which was noticed in that 

 i.sland during the gale of August 26, 1901. This is the green 

 page moth {Urania /eiln.s), which is native of South America, 

 and frequently appears in Trinidad in large numbers. About 

 a year ago several specimens of this insect were caught in 

 Barbados, and it seems probable that it is breeding there. 

 The food plant of the caterpillar in Trinidad has been 

 determined as Omphaha megacarpa. (See Agricnltural 

 Neirs, Vol. I, p[i. 5G and 108, and West Indian JiuUetin, 

 Vol III, p. 236) 



