42 



The Canadian Field-Naturalist 



[Vol. XXXVI 



color, slender in build and frequenters of vegeta- 

 tion such as flowers and shrubs rather than of 

 the ground. We have but one species in Mani- 

 toba, the Raspberry-cane Tree Cricket (Oecan- 

 thus nigricornis), so called from the damage it 

 does to cultivated raspberry canes while egg 

 laying. In reality, nearly any kind of hard- 

 stemmed plant is utilized for laying eggs in, the 

 eggs being placed in small slits made in the bark 

 by means of the insect's ovipositor. The practice 

 of ovipositing in the bark of trees, etc., seems to 

 be to protect the eggs only, as the young feed 

 upon leaves. Nevertheless, the habit is very 

 detrimental and often results in serious damage 

 being done to the stems of small fruit shrubs. 

 In Manitoba the wild rose is one of the most 

 frequently used plants. 



Acrididae 



The Acrididae or true locusts are the most 

 conspicuous of our grasshopper fauna and among 

 them are those that are recognized the world 

 over as pests of growing crops. One species, 

 doubtless belonging to the genus Acridium, pro- 

 bably constituted the sixth plague of Egypt. 

 Africa, Asia and South America all have their 

 plagues, which, at times, come in such numbers 

 as to darken the sky, and, with voracious appe- 

 tites, clean up every vestige of vegetation in the 

 districts visited. We have our destructive kinds 

 here which at times attain a ery large proportions. 

 In 1819 they cleaned up the crops of some of 

 our first settlers in the Lord Selkirk Settlement; 

 in 1871-75 the whole country seemed to be infest- 

 ed with them, and the old settlers can still recall 

 the flights that fell like snow from a clear sky, 

 dropping like a scourge upon the land beneath. 

 They can remember, too, the heaps of dead and 

 dying even over the land that is in the heart of 

 Winnipeg today. These were the Rocky Moun- 

 tain Locusts which came from climes adjacent to 

 the Rocky Mountains, their original breeding- 

 ground. Dryness and favorable winds multiplied 

 and brought them to our country, but eventually 

 our climate proved unsuitable and they either 

 died or flew elsewhere. 



There was a smaller outbreak of the Rocky 

 Mountain Locust in 1890 and yet another from 

 1900 to 1903, but that was the last and they have 

 not been seen in our territory since. The insect 

 is very rare now and some authorities think it has 

 become extinct, but this hardly seems probable. 

 Possibly, in the future, we may have other in- 

 vasions, but if we do we shall be prepared and will 

 know how to deal with them. 



While the old Rocky Mountain Locust has 

 vanished from our province, we have others that 

 are natives which, at times, develop into important 



pests. There has been an instance of this during 

 the last three years, when considerable damage 

 was done to crops, but the loss is not as it would 

 have been in the past. Efficient remedies have 

 been devised since then which enable us to cope 

 with the insects successfully. Probably few 

 people recognize how much has been done in the 

 way of grasshopper fighting during these last 

 three years, nor might they credit the fact that 

 poisoned bait has, in some instances, accounted 

 for a death rate of more than 200 bushels of 

 grasshoppers to the acre. 



The Acrididae are usually separated into three 

 sub-families: the Acridinae (Tryxalinae), (Edipo- 

 dinae and Locustinae. There is no very strict 

 line of demarcation between these, so I will not 

 go into details. The Acridinae are all clear- 

 winged grasshoppers with a rather slanting face. 

 They seldom occur in injurious numbers. 



The CEdipodinae, on the other hand, nearly 

 always have some coloring in their wings such as 

 yellow, red or black, while frequently the hind 

 wings are gorgeously colored so thar the insects 

 may be mistaken for a butterfly when on the 

 wing. In addition, the face is almost vertical 

 instead of slanting backwards. The sub-family 

 contains some of our largest locusts, such as 

 members of the genus Xanthippus and the well 

 known Carolina Grasshopper, which has black 

 inner wings bordered with yellow. Many of the 

 species, too, are very noisy, giving forth a loud 

 crackling sound as they fly. 



Not many of the CEdipodinae are of marked 

 economic importance but they are all grass 

 feeders and, therefore, have only to become 

 sufficiently numerous to turn into pests. One 

 of them has already done so on our prairies, 

 namely the Roadside Grasshopper (Camnula). 

 This is one of the few pale-winged forms, though 

 most specimens show a distinct yellowish tinge. 

 The species derives its name from its habit of 

 depositing its eggs in the sod-land along roadways, 

 though it also lays freely in other sodded areas. 

 It differs from other injurious species in depositing 

 its eggs amid clumps of grass instead of in small 

 bare spots. The fact that the Roadside Grass- 

 hopper is somewhat particular as to where it 

 lays its eggs often results in the insects bunching 

 up on suitable sod until such places are literally 

 crowded with eggs. So thick do they become 

 that we have counted more than 3,000 to a 

 square foot of sod. 



The Locustinae are told from the other sub- 

 families by the presence of a spine-like wart on 

 the prosternum between the front pair of legs. 

 All our species have clear whitish wings. It is 

 to this sub-family that vhe Rocky Mountain, the 



