INSECTS 



Sawfly larvae feeding exposed on trees, shrubs, etc., may be very easily mistaken for the larvae 

 of Lepidoptera (Butterflies and Moths). As a general rule they can be separated by the number of 

 legs ; lepidopterous larvae never have more than sixteen (six proper and ten pro-legs), while the larvae 

 of the sawfly may have twenty-two (six proper and sixteen pro-legs) ; but like everything in nature 

 there is no hard-and-fast line, therefore a great diversity will be found among the different species 

 in colour, form, and method of feeding. Several species may be mentioned to illustrate these 

 remarks, Leptocercus lur'tdiventris for instance ; the larvae of this species is flat, and lies stretched out 

 on the underside of the leaves of the elder, and resembles a scale insect rather than a caterpillar ; 

 while that of Eriocampoides limacina is more like a slug than a caterpillar in appearance and manner 

 of feeding, which is on the upper epidermis of the leaf at first ; as they grow they commence 

 feeding on the lower side of the leaf until every particle of green is consumed, leaving only a brown 

 skeleton, which shortly drops to the ground. Pear, apple, and plum trees often suffer from these 

 ' slugworms.* At the last change the slug-like skin is thrown off, then it appears as an ordinary 

 caterpillar. 



Another form of larva is that of PamphiUus depressus, which has no pro-legs on the abdominal 

 part for holding, consequently it has to spin a series of threads across the leaf, a sort of ladder 

 arrangement, wherever it desires to travel, sometimes connecting the outer edges of the leaves of the 

 alder for protection, or fastening two leaves together. 



The sawfly caterpillar which forces itself mostly on our notice is that of Pteronus ribesii, the 

 great destructor of the foliage of our gooseberry and currant bushes, eating the leaves, thereby 

 destroying the fruit ; the crop, however, may be saved by hand-picking when they first make their 

 appearance, which is indicated by numerous small holes in the leaves. The farmer is sometimes 

 troubled with Athalia spinarum,\ittitr known to him by the name of the ' nigger," black army,' etc., 

 from the black colour of the larvae ; these often attack the turnip crop, eating the leaves, causing 

 immense damage. 



Another sawfly the farmer dreads is Cephus pygmaeus, which attacks the stems of wheat and 

 barley, depositing its egg in the stem near the ground, the larva, eating upwards, consuming the 

 vital part of the stem ; when full fed it returns to the root, therein changes to a pupa, and where it 

 remains through the winter, ready to again commence the cycle of life after escaping from its 

 winter quarters. The larva eating the inside of the stem causes the plant to become too weak to 

 bear fruit, and the stem is usually blown down by the first storm. Any indication of an attack 

 should be noted, and to get rid of the pest the stubble after harvest should be gathered and burnt. 



Many of the sawfly larvae are conspicuous and feed exposed ; when this is the case the 

 majority are able to protect themselves by emitting a very disagreeable odour ; this no doubt suggests 

 an objectionable taste which would prevent a bird from attacking them a second time should it at 

 first sight have thought the larva a tempting morsel. This, however, does not prevent the ichneumon 

 fly from depositing its egg in the larva. 



Among the sawflies many species are known to be reproduced by virgin females ; in some 

 instances the offspring are all females, in another species all males, in a third they may be of both 

 sexes. In some species the males are so few and far between that many collections are without 



them. 



The writer does not know of any naturalist in the county who has devoted his entire energy 

 to this branch (Sawflies), therefore the list of captures, about 151, is only a portion of what might 

 be expected to occur in a county which has such a variety of vegetation on its moors, heaths, and 



hedgerows. 



The list is arranged according to Pastor Konow's system of nomenclature. 



LIST OF THE PHYTOPHAGOUS HYMENOPTERA OCCURRING IN 



THE COUNTY 



Neurotoma flaviventris, Ratz., Macrocephus linearis, Kirby, Hor- Cimbex femorata, Lin., ^'a'^ jf^r x ' 



Bickleigh rabiidge — connata,Vell.,P^««a//5Z)«V»-/V/ 



Pamphilius sylvarum, Kirby, Ivy- Cephus pygmaeus, Lin., Bickleigh, Trichiosoma lucorum, Lin., Crab- 



bridge, 26 April 26 June tree, Plymouth 



— betulae Lin., Z)^w» (Stephens) Sirex gigas, Lin., P^»!3n<<gi?,- Ctf»» — betuleti, Klg., Church Lane, 



— depressus, Cam. Gen. dist. ^f'^ ^ , , e luj au- ^""!'"'''\. „.,,., 



— sylvaticus,Lin.,iV.Z)m«(Par- — noctiho, Fab.' Several bred Abia sericea, Lm., Bukleigh, 



gjj\ ' from pine trees 22 April 



— inanitUS, VilL, Ivybrtdge ^ 1 yj^j^ ^jj^jj , ^^^ ^^3 supposed to be ' Marked thus { X ) have been recorded 

 Tanus cynosbati, Fab., Horrabridge ; juvencus, F. The true juvencus has not by the late Edward Parfitt for the Exeter 



Bickleigh been observed in England. district. 



167 



