Also, there are always at least six pair of abdominal prolegs on sawflies. Abdominal prolegs look like fleshy projections that are grasping the wheat stem. Prolegs are lost during the molt to the adult stage. However, I have never seen them in numbers large enough to hurt the wheat or oats. In a sweep net, however, early instar spittlebug nymphs and latter instar potato leafhopper nymphs are similar in size.
Spittle bugs tend to be a darker shade of green and leafhopper nymphs tend to be yellow-green.
Leafhopper nymphs will run sideways, or backward or forward when disturbed. Spittlebug nymphs movement tends to be much slower and more deliberate. Latter instar spittlebug nymphs are shaped like small toads and much larger than leafhopper nymphs. You can also throw pea aphid and plant bug nymphs into the confusing array of insects taken in alfalfa seep samples. You will need fairly high magnification to pick out the cornicles.