!78 



THE AGRICULTURAL NEWS. 



NOVKMBER -28, 1908. 



INSECT NOTES.* 



The White Ant (Ten,,,. y!„,;-j.,-s, Koll.). 



Insects of the family Termitidae, the faiiiil}- to 

 which the ' white ants' belong', feed on wood and dead 

 vegetable matter, and live socially in mixed colonies of 

 sterile and fertile individuals. The term 'white ant,' 

 by which these insects are known, is entirely inappro- 

 priate in so far as it indicates aii3'relat!onship with the 

 true ants, as they are not ants, but belong to the order 

 Tsoptera, being closely allied to the boolv-lice. 



The popular acijuaintaiK-e with the termite is derivetl 

 from seeing it on its nuptial Higlit when the small, brown, 

 winged insects emerge from crevices in buildings and ground. 

 These are the colonizing forms, and not the ones which 

 actually do the damage, for the real depredators are the soft- 

 bodied, large-headed, milky white soldiers and workers. Xo 

 insect occurring in houses is capable of doing greater damage 

 than Tc-iiirx Jfii,;'pcv, and since their entrance to buildings 

 i^ effected by soil channels, and their work cannot usually be 

 iletected before considerable damage has been done, not only 

 their eradication, but their detection is a difficult matter. 



In every colony thcve are four forms : males, females, 

 soldiers, and workers. The males have a pair of comjiound 

 I'yes placeil just above the antennal fossae, and when young, 

 iwo pairs of large membranous and appro.ximately equal 

 wings, projecting beyond the ape.\ of the abdomen when at 

 rest. They live permanently with the females. The females 

 when young closely resemble the males, but later, when they 

 liccome moiliers of colonies, this resemblance is not .so close. 

 The soldiers are sterile, wingless, and usually blind. Their 

 heads are chitinous, strong, and peculiarly adapted for 

 defence. They act as protectors of the colony, although 

 occasionally assisting the workers. The workers are sterile, 

 wingless, usually blind, liut little chitini/.ed, having .-.h(Ut 

 and pouerlul jaws, and larval in appcarat'.ce. Tlicy atten<l ' 

 to all the duties of the colony, such as building the nests, 

 caring for the j'oung, and ministering to the wants of the 

 queen. All except the migratory winged forms are inca|)- 

 able of enduring sunlight, as the soft delicate bodies of the 

 other forms shrivel when expo.sed, and, con.sequently, all tluir 

 o]>ei-ations are done under shelter. 



.\t the timi' of tlu- niqitial IIi.L;lit, the winged t'onns 

 emerge in pairs, and, under favourable conditions, each j)air 

 may e-itablish a new colony, but as they are preyed upon by 

 many in.sectivorous animals, this rarely lia]ipens. As .soon as 

 a king and queen have estal>lished a new colony, they superin- 

 tend the rearing of the first brood of workers and soldiers 

 until these are able to assume their special duties in the colony. 

 Hen'-eforth, the ipieen loses all power of locomotion, is 

 constantly fed by the workers, and her size increa.ses consider- 

 al)ly. She now becomes an egg laying m»clune, laying many 

 thousands of I'ggs per day. When any accident befalls the 

 queen, a ' supplementary ipieen ' is develojjed from a very 

 young larva, being smaller, however, than a true (jueen, but 

 .serving the purpo.se of egg-layiny equally as well. 



As so many of the colonizing forms are destroyed during 

 their nuptial Might, the more usual rule of the formation of 

 a new colony is tlu' splitting up of old colonies. .\s methods 

 of [ireventiou, and reniedit's against white ants, the following 



may be mentirmed : — (l)Ooat all foundation tind)ers with tar. 

 (2) Build the foundations of iiuiidings entirely of brick, stone, 

 or concrete. (."5) Fumigation with hydrocyanic acid gas at 

 the strength of I oz. of potassium cyanide per 100 cubic feet 

 of space. (To make this gas, the required number (,,■) of ounces 

 of potassium cyanide is weighed out : to this is added twice 

 the number (2.;) of Huid ounces of sulphuric acid, and four 

 times the number (4./ ) of fluid ounces of water.) Fumigate in 

 n tight room to which access cannot be gained during the 

 operation as the gas is a most deadly poison. After the 

 room has been closed, jait the acid and water into an ,-n-the7i- 

 ,i<,iri; vessel and drop into- it the cyanide contained in a bag 

 attached to a string which runs freely through a key-hole. 

 After fumigation has gone on from one to two hour.s, oiien 

 the room from the (i,i.txi<h and allow it to air fir not less 

 than six hours before entering. 



* The I:isect Notes in this nmubijr, as in the lust issue of 

 the A(frlniltiinil A'lir.s-, were contril)Utud by Mr. C. C. Gowdey, 

 U.Sc, who has for a .sliort time past t>een att;iclie;l to tlu' 

 Inqiei'ial ])e|K'.rlnivnt nf .XgricnUure as Hniior:n-y .\ssistant 

 Kntoni'ifiL'i.-.t. 



The Cattle Tick iH<,»i,hiln.-< amuilntus). 



Texas fever (known also as splenetic or tick fever) 

 is a disease caused by a microscopic organism whicb 

 lives in the blood and destroys the red corpuscles of 

 the animal attacked. In sucking blood from fever- 

 infected, or immune animals (i.e., those animals which 

 have had an attack of Texas fever and recovered there- 

 from), a nutviber of the germs is necessarily withdrawn 

 by the tick, along with the blood. When the female 

 tick deposits eggs, the ^erms pass into the eggs and 

 later into the ' seed-ticks ' hatching from these eofirs. 

 As soon as these ' seed-tieks ' got upon a bovine animal 

 and begin the bloo(i-sucking process, the germs of the 

 fever pass from them into the system of the host 

 animal, resulting in an attack of fever. 



The presence of the germ is not necessary to the develop- 

 ment and ri'production of the tick, but the tick is an 

 absolutely necessary agent for the transmission of Texas fever 

 from one animal to another. 



Lifi-limlori/ and Dixfiiljiifiiiii. 'I'lie cattle tick lieing 

 a |iarasite derives its food cntiiely liy sucking blood fiom the 

 animal — cow, ox, calf, deer, and occasionallv horse and 

 mule— to which it is attached. The female tick on reaching 

 nraturity, releases her hold upon the animal, drops to the 

 ground, and after from two to five days begins egg-layino-. 

 The deposition of eggs is continued for eight to tilteen day.s, 

 each female depositing between l,.'iO(> to l,.")00 eggs duii'ni; 

 this period, after which slie dies. 



The eggs thus dei)osited on the ground hatch i]i from 

 seventeen to twenty-five days, and as soon as they have left 

 the egg-shell, the young ticks or ' seed-ticks" crawl up the 

 blades of grass and collect together near the to|p. Un 

 coming into contact with a piLssing animal, the .seed-ticks 

 .select suitable ])o.sitions, insert their mouth-parts, and 

 commence sucking blood, d'rowth of both males an<l females 

 at this time is rapid, and the in.sects nuuilt twice during tlieir 

 growth. The expansion of the abdomen of the females, 

 in part due to the formation of eggs, takes place after 

 the second UKudt. The male ticks do not become nearly so 

 large as the swollen females, and may be easily mistaken 

 tor partly-grown females. In from twenty-one to forty live 

 day.s, depending on the condition nf the host, the growth of 

 the female is completed. 



For a very long time this cat:le tick has been known to 

 inhabit Europe, Africa, India, I'.orneo, South and Central 

 America, Mexico, Texas, and the West Indies, 



