INSECTS 



JASSIDAE 



Athysanus, Burm. 

 § — grisescens, Zett. 

 * — communis, J. Sahl. 

 * — obscurellus, Kbm. 

 *^ obsoletus, Kbm. 



Deltocephalus, Burm. 



— socialis, Flor. Local 



— striatus, Lin. Local 



t — punctum, Flor. Stonehouse ; 

 Plymouth. Flew into the 

 house (Bignell) 



— pulicaris, Fall. Local 

 AUygus, Fieb. 



§ — modestus, Fieb. 

 * — mixtus, Fab. 



Thamnotettix, Zett. 

 § — subfuscula, Fall. 

 * — splendidula. Fab. 

 * — crocea, H. S. 



Limotettix, J. Sahl. 

 5 — quadrinotata, Fab. 

 \ — nigricornis, J. Sahl. 



Cicadula, Fieb. 

 * — sexnotata, Fall. 



Gnathodus, Fieb. 

 5 — punctatus, Thunb. 



TYPHLOCYBIDAE 



Alebra, Fieb. 

 + — albostriella, Fall. 



Kybos, Fieb. 

 § — smaragdulus, Fall. 



Chlorita, Fieb. 

 § — viridula, Fall. 



Eupteryx, Curt. 

 § — vittatus, Lin. 

 * — urticae, Fab. 

 § — stachydearum, Hardy 

 * — melissae, Curt. 

 * — auratus, Lin. 



— filicum, Newm. On ferns, 

 in a fernery, Plymouth (Big- 

 nell) 

 •— pulchellus, Fall. 

 * — concinna. Germ. 



Typhlocyba, Germ. 

 § — sexpunctata. Fall. 

 * — ulmi, Lin. 

 * — tenerrima, H. S. 

 * — aurovittata, Dougl. 

 * — Lethierryi, Edw. 

 * — rosae, Lin. 

 * — quercus. Fab. 

 * — geometrica, Schr. 



APHIDIDAE 



APHALARIDAE 



Rhinocola, FOrst. 

 * — ericae. Curt. 



PSYLLIDAE 



Psyllopsis, F. Low. 

 * — fraxini, Lin. 



Psylla, F. Law. 

 § — mali, Schbdg. 

 * — pineti, Flor. 

 * — salicicola, FOrst. 

 * — Forsteri, Flor. 

 * — alni, Lin. 



TRIOZIDAE 



Trichopsylla, Thoms. 

 § — Walkeri, Farst. 



Trioza, FOrst. 

 * — urticae, Lin. 

 * — crithmi, F. LOw ' 

 * — remota, Farst. 

 * — albiventris, Farst. 



' Stonehouse ; Plymouth. Abundant on 

 the rocks, where the Samphire (Crithmum 

 maritimum) grows freely. During August 

 they may be seen in all stages, eggs, larvae, 

 pupae, and the perfect insect. (Bignell) 



The increase of Aphides (generally known as blight) in a few days on certain plants appears 

 marvellous ; but when the life history of an aphis is known it does not remain so great a 

 wonder. It may, therefore, be interesting to know something of its life history. As a general rule 

 the first aphis in the spring proceeds from an egg, and it requires about twenty days to arrive at 

 maturity ; it then commences to bring forth its young at the rate of from eight to twenty a 

 day ; one old writer says twenty-five a day ; that must have been a very exceptional case ; the 

 number depends entirely on heat and the food supply. Viviparous females, without the intervention 

 of the male, will again under favourable conditions begin to reproduce their species in five or six days. 

 Males and oviparous females are not produced until the end of the breeding season, which is generally 

 with the first indication of the autumnal change, i.e. by those that continued breeding viviparously : 

 for some species may have only a few broods. There is no hard-and-fast line in nature, for what a 

 hundred may do, the remainder do not do ; both, however, attain the same end, but in different ways. 



Kyber remarks that although the duration of the state of viviparousness is in a certain sense 

 almost unlimited, yet in great measure it is controlled and determined by insufficient food and 

 reduced temperature. Further, he says that certain species, feeding on herbaceous plants which 

 fruit early in the year and then wither, produce males and apterous oviparous females in the middle 

 of the summer. Also, that the same thing occurs when the food plants rapidly become woody in 

 texture. On the contrary, where Aphides get their nourishment from plants persistent throughout 

 the year, the males and oviparous females as a rule do not appear until late autumn or early winter. 

 He found that the rose aphis might be kept in its viviparous condition for years if the habitat were 

 artificially warmed and a good supply of succulent food provided. He kept them for four consecutive 

 years ; at the expiration of that time the energy of the power of the agamic reproduction was undimi- 

 nished. The rose aphis may live a month or longer under favourable circumstances in the garden. 



De Geer's most important deductions may be thus summarized : — 



First. — That the oviparous forms never produced living young. 

 Second. — That the viviparous female never deposited eggs. 



Third. That at the end of the autumn the viviparous females in most cases produced males 



and females, which through oviposition provided the species for the ensuing year, the 

 egg retaining its vitality throughout the rigour of winter. 



Fourth. That if cold weather did not supervene, the male and the oviparous females did not 



occur at all. 

 By natural law where the power of reproduction is great there must be a number of enemies 

 to keep it in check ; no insect is so productive as the Aphis, and no insect has so many enemies, 

 or of such various kinds. The larvae of fifty-eight species of hovering flies {Syrphidae). 



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