This week brings us a dragonfly- an insect with which we are somewhat familiar. These creatures benefit humans by eating mosquitoes, both in the larval and adult forms, and they cause absolutely no harm to people. So, if you view them with disgust or disdain then you should be ashamed of yourself. Dragonflies are also the world's most acrobatic and agile flyers, largely because each of their wings operates independently. The image of the wing base illustrates part of the complicated external morphology that connects the wings to internal musculature.

In the air, the dragonflies catch prey in their legs, which are typically bristling with stout hairs that create prevent their prey from escaping. Sometimes you may see dragonflies patrolling a particular part of a pond or lake shore. This is a male defending his territory from other males. If a female finds his territory to be a suitable place to lay eggs, she may mate with him.

This species is from Florida, it is about 1 inch long and belongs to the family Libellulidae.

Baeus

This unpredictable interval time brings you an image of Baeus. Parasitoid wasps in this genus attack the eggs of spiders. The plucky females nibble their way through the silk covering of spider egg sacs and parasitize the eggs inside. Males have wings, in the females the wings are vestigial. The round, spherical shape of these wasps reflects the shape of the egg in which they develop. They are very small, typically less than 1 millimeter in length, and are probably not noticed at all by adult spiders.

If you have a cellar, attic, or windows full of cobwebs, you may be in close proximity to these creatures.

This week brings us two specimens that highlight independent yet similar modifications to the abdomen that maximize the length of the ovipositor (the syringe-like structure for inserting eggs into a host).

Idris is a close relative of Baeus, last week's subject, and it also parasitizes spider eggs. The black arrow points to an area known as the "horn" in which part of the ovipositor retracts. This extension will permit a longer ovipositor that, when extended, will reach as many spider eggs as possible in an egg sac. This specimen is from Malaysia.

Synopeas is a member of the subfamily Platygastrinae which parasitizes the eggs and early larvae of gall flies (Cecidomyiidae).This Greek specimen has a modification on the underside of the abdomen in which the retracted ovipositor curls. A longer ovipositor will help Synopeas reach its host inside flowers and plant tissues.

If you have a yard, both of these genera can probably be found there.

Both specimens are ~2.5mm in length.

Tetrabaeus americanus

This week brings a parasitic wasp, Tetrabaeus americanus, that kills other wasps. Females of some species of predatory wasps (Crabronidae) hollow out the pith of sumac twigs to create empty cells. The predatory wasp females then lay eggs in these cells and pack them with prey items for their larval offspring to eat. Tiny females of Tetrabaeus americanus lay eggs inside these much larger larvae that, upon hatching, will consume the innards of their host.

Syrphidae

This week brings us a very common kind of insect that you will surely see if you look for it. This image is of a fly in the family Syphidae, recently collected from the base of an Amaryllis plant by a local enthusiast. Sometimes called flower flies, they often mimic bees and wasps and can usually be found hovering around flowers, some even mimic the buzzing sound made by bees in flight! The short antennae with the bristle at their tips and the single pair of wings indicate that this is a fly and not a bumblebee (which has much longer antennae and two pairs of flight wings). The larvae of these flies have a wide variety of habits; many are predaceous on aphids and thus beneficial to gardeners.

Stalk-eyed fly

This week brings us a fly from Ghana in the family Diopsidae, also called stalk-eyed flies. Why do would these flies have such long eye stalks? To impress female flies of course!

These flies feed primarily on bacteria, fungi and decaying organic matter. A less dramatic species in this family (Sphyracephala brevicornis)is found in North America and can be collected in the Northeastern United States as late as Thanksgiving.

Stink bug and Trissolcus

This week brings us a stinkbug (Hemiptera: Pentatomidae) collected in my home. At least one of you also has these in your house. Don't worry, they are harmless. The worst possible damage they could do is feed on your house plants, and this is unlikely. Stinkbugs are a large and economically important groups, containing many pest species that feed on a wide variety of plant crops, and you can find them almost everywhere

The second image is a species of parasitoid wasp in the genus Trissolcus (Hymenoptera: Telenominae). One species in this group, Trissolcus basalis, attacks the eggs of stinkbugs, including the nefarious Nezara viridula, one of the world's most infamous stink bug pests.

So, remember that parasitoid wasps can be your friend!