246 



TlIYSANOPTEKA.- 



-INSECTS.- 



-LlMOTHRIPS. 



digging long trenches, two or three feet deep, into which 

 tlie Satlones are driven, nolentes volentes. When tlie 

 trenches are lialf filled with the young insects, the earth 

 is shovelled back on them and they are buried. Myriads 

 are driven into rivers and drowned. 



Every fifty years the Chapulin is said to appear in 

 myriads, and their devastation lasts from five to seven 

 years, when it entirely disappears. There is no doubt 

 tliat, like other insects, these periodical visits are use- 

 ful in a moral, and may be in a physical way as well, 

 to the inhabitants. The insect is from two and a half 

 to four inches long, and specimens have been met with 

 five inches in length. 



Tlie Petasida ephippigera is a grasshopper from 

 Korth Australia, of a bright brick colour dotted with 

 blue. The thorax is much dilated behind, being pro- 

 jected over the base of the wings somewhat like a saddle; 

 from this circumstance its specific name is derived — 

 epliippiata, saddled. The species was first obtained on 

 the voyage of the Beagle, when engaged on the survey 



of the north coast of Australia. At first sight this 

 insect has a strong external resemblance to some cf 

 the African grasshoppers, but it belongs to quite a 

 distinct genus, which may be known by the above 

 mentioned character. The insect is nearly two inches 

 long, and is "the grasshopper" referred to at p. 481 

 of Dr. Leichardt's " Journey." 



There is figured, in the great work on the Dutch 

 East India Possessions,* a curious insect, the Chcn-ce- 

 tijpus gallinacens, a native of Sakoembang. It has the 

 thorax, or at least the pronotum part of the thorax, 

 produced as far as the last dorsal joint ; its posterior 

 angle is very sharp. In this subgenus the anterior 

 margin of the prosternum does not surround the mouth. 

 A genus where that part does not surround the mouth 

 is named Hymenoies. 



Fig. 8 of Plate 5 shows the Acrydium lipunclatum 

 or Tettix hipunctata, in which the prothorax is greatly 

 developed posteriorly. It is a British species. There 

 are twenty-six species recorded as British. 



Sub-order— THYSANOPTEHA. 



This order of insects contains a host of minute crea- 

 tines, which, both in their perfect and larva state, 

 frequent Bowers, or live under the bark of trees. They 

 are nearly all of very minute size, very few of them 

 exceeding a line in length. The figure in the mar- 

 gin shows one of these highly magnified. The largest 

 are some Australian species of Idolothrips, one of 



Fib isi. 



Thrips, greatly magnified. 



which is four lines or more in length. The body is 

 elongated and depressed. The following characters 

 are those of the order: — The wings are generally four, 

 alike, long, narrow, membranous, without reticulations, 

 the edges with long cilife ; when at rest these wings 

 are laid horizontally along the back. The mouth is 

 situated on the underside, and has two setiform man- 

 dibles, two broad adpressed palpigerous maxilla3. The 



tarsi are two-jointed, and vesiculosa at the tip,| and 

 without claws. The antennse have few joints. De 

 Geer noticed that when the Thrips presses the vesicle 

 of its feet against the surface on which it walks, it 

 expands and appears concave, which led him to imagine 

 that it acted like a cupping glass. 



The pupa and propupa, as Mr. Halida}' calls tho 

 two states the insect passes through after leaving its 

 larva conditions, are slower in their motions than tho 

 perfect insects. 



Tlie Thysanoptera are found on various plants, 

 some of them being exceedingly injurious, particularly 

 in hot-houses. The leaves of vines and otlier plants 

 on which they muster are marked with small decayed 

 patches. 



One species (^Limolhrips cerealium) infests our 

 wheat crops, and destro)'8 them at times. The Rev. 

 Mr. Kirby described this insect under the name of 

 Thrips physaptts. It takes up its place between the 

 inner valve of the corolla and the grain, and seems to 

 fix its beak in the bottom of the seed. By extracting 

 the moisture it causes the seed to shrivel up, and be- 

 come what the farmers call " pungled." This species, 

 it would appear, also gnaws the stems above the knots, 

 and causes the abortion of the ear. In 1805, about a 

 third of the wheat crop in Piedmont is said to have 

 been destroyed by this insect ; and in the same year, 

 the same crops suffered much in this country from a 

 similar cause. 



In Tuscany, another species of Thrips proves very 

 injurious to the olive-tree. It fixes itself on the under- 



• Verhandelingen over de Naturlijke Geschiedens, &c. — 

 Orthoptera, by W. De Haan and Hagonbach ; p. 165, PI. 22, 

 fig. 5. 



t Dumeril, from this structure, gave these insects the name 

 of Physapoda (Zool. Anal. p. 2G8). Mr. H.itiday, who first 

 characterized the order, gave it the name Thysanopoila, but 

 substituted Dumeril's name for it in a synopsis of the order 

 given in Walker's Homopterous Insects, in the collection of the 

 British Museum, p. 1094. 



